Israel’s top general has said the country is preparing for a possible ground operation into Lebanon amid growing international pressure for a negotiated ceasefire between Hezbollah and Israel.

As an intense bombing campaign inside Lebanon stretched into a third day, Israel’s chief of staff, Maj Gen Herzi Halevi, said the airstrikes aimed to destroy Hezbollah infrastructure and prepare for the possibility of Israeli troops crossing the border.

Halevi told troops during a visit to Israel’s north: “We are preparing the process of a manoeuvre, which means your military boots, your manoeuvring boots, will enter enemy territory, enter villages that Hezbollah has prepared as large military outposts, with underground infrastructure, staging points and launchpads into our territory [from which to] carry out attacks on Israeli civilians.”

Despite Halevi’s comments, the Pentagon spokesperson Sabrina Singh said a ground offensive did not appear “imminent”.

Earlier on Wednesday, Hezbollah aimed a long-range missile at Tel Aviv and Israel targeted the mountains north of Beirut for the first time in the war, drawing an Israeli warning that it was preparing a major response.

Halevi’s comments came amid growing pressure from the US for a pause in the fighting and a warning from Joe Biden over the need to avoid “all-out war” in the region.

“An all-out war is possible,” the US president told ABC, adding that he believed an opportunity also existed “to have a settlement that can fundamentally change the whole region”.

Biden, who has been widely criticised for mishandling the escalating Middle East crisis, suggested that getting Israel and Hezbollah to agree to a ceasefire could help achieve a cessation of hostilities between Israel and Hamas militants in Gaza.

But while the US-led initiative to secure a ceasefire with Hezbollah has the support of France and Arab countries, it relies on Hezbollah agreeing to stop firing on Israel before any ceasefire in Gaza is secured. France has called a UN security council meeting on Lebanon for Wednesday to discuss ideas around de-escalation.

Hezbollah has long insisted that any cessation of firing on its part is contingent on an end to Israeli operations in Gaza, where negotiations over a ceasefire-for-hostages deal have been bogged down for months.

It was unclear whether Halevi’s public comments and the diplomatic efforts were connected, with the Israeli prime minister, Benjamin Netanyahu, due to be out of the country for four days from Thursday for the UN general assembly.

Later on Wednesday evening, Israeli officials were pessimistic about any chance of a ceasefire.

In Lebanon, authorities said on Wednesday that the death toll after three days of Israeli bombardment had passed 600, with thousands more injured. The UN said 90,000 people had been displaced since Monday, on top of more than 200,000 people who had left their homes in southern Lebanon over the past year as Hezbollah and Israel exchanged fire over the border.

With Israel and Hezbollah now in effect at war, world leaders gathered for the UN general assembly in New York repeatedly warned of the dangers of a full-blown regional conflict.

But as they called for de-escalation, they prepared for the opposite: from Moscow to London to Washington, governments told citizens in Lebanon to return home while they could, as airlines cancelled flights from Beirut.

Israel says its campaign against Hezbollah is needed so 60,000 people evacuated from border regions can return home. It has so far been confined to aerial attacks, but on Wednesday, Israel’s military called up two reserve brigades for operations in the north and signalled that troops would soon be ready to cross the border.

Maj Gen Uri Gordin, the head of the Israel Defense Forces (IDF) northern command, told soldiers from an armoured corps that the war was in a “different phase” and they should “strongly prepare” for action. “We need to change the security situation,” he told troops in a clip shared on army radio.

Hundreds of thousands of people have fled southern Lebanon to escape Israeli bombs, but Wednesday’s strike on Maysaara, about 60 miles (100km) north of the border, fuelled fears that Israel could also unleash heavy attacks on other parts of the country.

In the scramble to save their lives, thousands of people had reversed the refugee flow seen for more than a decade and crossed from Lebanon into Syria, aid agencies said.

Hezbollah attempted to strike Tel Aviv for the first time on Wednesday but Israel intercepted the surface-to-surface missile with air defences, and no damage was reported.

The Shia militant group said it was targeting intelligence headquarters, in an apparent signal that it can still pose a serious threat even after days of intensive Israeli attacks which have killed many top commanders and destroyed much of its arsenal.

An Israeli military spokesperson said the unguided missile had been heading towards civilian areas along the coast. “The Mossad headquarters is not in that area; it is a bit east and north of that area,” the IDF’s international spokesperson, Lt Col Nadav Shoshani, told a briefing.

In the southern Israeli city of Eilat, a building near the port was struck by a drone, injuring two people in an attack claimed by an Iranian-backed militia in Iraq.

Israel estimated that Hezbollah had 150,000 rockets and missiles at the start of the war and has not said how many have been destroyed. Senior commanders killed include the head of the elite Radwan force last week, and on Tuesday the head of the missile and rocket force, Ibrahim Qubaisi.

Israel’s successful strikes have decimated the top of Hezbollah’s chain of command, but Iran’s supreme leader, Ayatollah Ali Khamenei, one of Hezbollah’s key backers, said on Wednesday that the group would survive the death of senior leaders, Reuters reported.

“The organisational strength and human resources of Hezbollah is very strong and will not be critically hit by the killing of a senior commander, even if that is clearly a loss,” he said.

Over decades of conflict, Hezbollah has previously managed to rebound from heavy blows and fight Israeli forces to a standstill, despite a vast disparity in military technology.

As it braces for further retaliation, Israel has brought in tighter restrictions, which include school closures, for more than 1 million people in northern parts of the country, including the city of Haifa. One rocket hit an assisted living home in Safed City, starting a fire, but no casualties were reported.

In Tel Aviv, after the morning missile scare, life returned to something like normal on Wednesday, with kite surfers enjoying the sea off its beaches.

Bar Zinderman, 34, said racing to a bomb shelter with his two-year-old son Ar on Wednesday morning had been frightening, but that he backed the decision to attack Hezbollah.

“I think we are doing the right thing,” he said. “We had no choice but to fight against two enemies at our borders, who forced thousands of my fellow countrymen to evacuate. I hope that our pressure on them will soon lead to an agreement to end this war.”

Nabih Berri, the speaker of Lebanon’s parliament, said he was making “great efforts” to reach a diplomatic solution between Israel and Hezbollah, in coordination with the US and his own government. The next 24 hours would be decisive, he added.

Lebanon’s foreign minister, Abdallah Bou Habib, said the US was the only country that could end the conflict, but expressed disappointment after Biden addressed the UN on Tuesday. His remarks were “not strong” and “would not solve the Lebanese problem”, Bou Habib said.

The UK is closely monitoring Beirut’s international airport amid fears it may be forced to close by escalating fighting between Israel and Hezbollah, which would probably lead to an evacuation of British and other foreign nationals from Lebanon.

Defence sources said a halt to commercial flights out of the country would be a “big trigger” to launch what would most probably be an international evacuation by sea, though for now an emergency rescue is not thought imminent.

Keir Starmer, the UK prime minister, called on Britons to leave promptly via commercial flights, and would not be drawn on describing how a rescue might be conducted if air travel was suspended.

“I have a very important message for British nationals in Lebanon which is: the time to leave is now. The contingency plans are being ramped up but don’t wait for those, there are still commercial flights. It’s very important that they hear my message, which is to leave and to leave immediately,” Starmer said.

Later Starmer, who is in New York for the UN general assembly, was asked if it might be necessary to deploy British troops in Lebanon to help with a rescue. “I’m not going to get into the details of evacuation plans,” he said, but added that ministers had “put contingency measures in place” – and warned that fighting in Lebanon was escalating “almost hour on hour”.

On Tuesday, Britain said it was moving 700 troops to Cyprus, including members of the Royal Marines, to “focus on contingency planning” and help those leaving by commercial routes. They would be supported by members of Border Force and officials from the Foreign Office to help with advice and immigration processing.

It is estimated there are about 6,000 British nationals and dual nationals, as well as their dependants, remaining in Lebanon. About 10,000 more have left in the last week. The number of US citizens was estimated at 86,000 in 2022, while French citizens in the country are thought to number about 23,000.

A No 10 spokesperson said: “We have always said we stand by Israel’s right to self-defence but the PM’s message is that we are concerned by the situation and we need to see an immediate ceasefire and a focus on an immediate political settlement.”

Israeli airstrikes over the past three days have been concentrated in Hezbollah’s stronghold in south Lebanon, aimed at forcing the Iran-aligned militant group to halt attacks on northern Israel. More than 500 Lebanese have been killed in the bombing.

However, the two sides appear to be gradually escalating, with Israel bombing the mountains north of Beirut and Hezbollah targeting Tel Aviv on Wednesday.

Israeli experts have accused Hezbollah of hiding long-range missile launch sites in areas near the capital. Any bombing in that area would represent a significant escalation.

The Lebanese carrier Middle East Airlines is still operating flights from Beirut to cities in Europe and Middle East, though many other carriers have suspended their services. However, it is not immediately clear how many seats are available.

British sources said the most likely evacuation route would be via sea to Cyprus, though the situation is described as changeable. Navy vessels available are the auxiliary ship Mounts Bay, a military landing craft that can carry several hundred, and the warship HMS Duncan, though merchant shipping could also be deployed.

That scenario would mirror the rescue from Beirut that was organised during the last Lebanese war in July 2006. Warships evacuated 4,500 British nationals, starting five days after Israel announced an air and sea blockade of Lebanon in response to a cross-border raid by Hezbollah.

An airlift is an alternative possibility if it is safe to conduct one. British troops could be deployed, with the permission of the Lebanese government, to secure a port or airport evacuation area as happened previously in Afghanistan. But there is no prospect of troops rescuing Britons from their homes in the country.

John Healey, the defence secretary, chaired a meeting with ministers, intelligence heads and diplomats on Tuesday afternoon to discuss evacuation plans. Discussions continued on Wednesday but there were no immediate plans to hold a Cobra emergency meeting, a probable prelude to an evacuation.

Labour ministers are anxious to avoid the chaos of the evacuation of Kabul in Afghanistan in the summer of 2021, when thousands of people crowded at the airport in the hope of escape, while the Foreign Office in particular was criticised for being unprepared to handle the crisis.

Rami Mortada, Lebanon’s ambassador to the UK, said his country would be ready to help with evacuations. “The situation is unfolding by the hour and it looks like a very worrying situation for us Lebanese and clearly for the expat community in Lebanon. We would be ready to provide all the assistance needed,” he said.

No two wars are alike, even those fought between the same two combatants on the same terrain. But many of the challenges remain the same.

Israel’s most senior military commander has told troops that airstrikes will continue inside Lebanon as the Israeli military prepares for a possible ground operation. If its forces do cross the northern border they are likely to face obstacles they have seen before.

When Israeli tanks rolled into southern Lebanon in 2006 (not for the first time) they found an opponent who had changed dramatically since Israel’s withdrawal from Lebanon six years earlier.

Even in that short time, Hezbollah had organised and developed its capabilities. In the scrubby border zone overlooked by steep rocky ridges, combat tunnels had been prepared. New tactics and weapons had been adapted that would harry the Israeli forces as they entered.

Tanks in particular were vulnerable to anti-tank missiles, while fighters from Hezbollah and its allied group the Amal Movement fired mortars on the units of advancing Israeli infantry as they picked they way through groves and tobacco plots.

For those (including this writer) who witnessed the fighting close up, it was instructive.

In that war – as in this one – Israeli jets and drones controlled the air, pounding infrastructure and Hezbollah positions unopposed. Israeli gunboats, often sitting over the horizon, shelled the coast, threatening the main coastal highway daily. But approaching the border, it was a very different picture.

Then, as now, Hezbollah had well-prepared positions. Rockets would erupt from a hidden position on nearby hillsides, drawing Israeli counter-strikes, both from jets and artillery on the border, that it seemed impossible to survive. But often, after a pause of a few hours, the rockets would fire again from the same place, initiating a repeat of the cycle.

In his comments to soldiers, the Israeli chief of staff, Herzi Halevi, appeared to nod to the reality that any ground incursion, if it is ordered, would be difficult and opposed.

“We are preparing the process of a manoeuvre, which means your military boots, your manoeuvring boots, will enter enemy territory, enter villages that Hezbollah has prepared as large military outposts, with underground infrastructure, staging points, and launchpads into our territory [from which to] carry out attacks on Israeli civilians,” he told Israel Defense Forces troops on Wednesday.

“[In] your entry into those areas with force, your encounter with Hezbollah operatives, [you] will show them what it means to face a professional, highly skilled, and battle-experienced force. You are coming in much stronger and far more experienced than they are. You will go in, destroy the enemy there, and decisively destroy their infrastructure.”

The reality is that any ground campaign will be a far more complex undertaking than the intelligence-led attacks Israel has been pursuing in its exploding-pager gambit and the subsequent airstrikes.

The failures of the 2006 war – outlined in the subsequent Winograd commission – had their own fathers, including in a troika of inexperienced Israeli wartime leaders: the then chief of staff, Dan Halutz, a former fighter pilot who struggled to coordinate ground movements, as well as the then prime minister, Ehud Olmert, and defence minister, Amir Peretz.

As the Haaretz military correspondent Amos Harel wrote in 2016, a decade after the war: “IDF divisions were moved around aimlessly, with the government and army incapable of defining a manoeuvre that would gain the upper hand.”

And while the IDF has improved its armour to better defend against mobile anti-tank weapons and prepare for fighting in Lebanon, it remains unclear whether an Israel ground incursion can avoid the same pitfalls. Or whether, indeed, its goals any more realistic.

Hezbollah is much better armed than it was in 2006, its militants more combat-experienced after years fighting in Syria, but Israel seems to be falling into the same conceptual trap of misunderstanding the nature of the Islamist group.

While the pager operation and Israeli strikes have been successful in removing a layer of leadership and command and control, the essence of Hezbollah as a Lebanese force – as opposed to its function as a strategic proxy for Iran – ultimately remains intact.

At its heart it remains a locally embedded force dispersed through cities, villages and the countryside with a single and well-understood task: to oppose Israeli troops.

And while Hezbollah has experienced a moment of “shock and awe” in the pager and walkie-talkie attacks, and airstrikes, Israel has its own disadvantages – not least an increasing overstretch not only in its military capacity, but in a growing exhaustion in Israeli society after a year of war.

Many of the same units that have been fighting in Gaza have been moved north. A deepening crisis on the West Bank is also draining as the conflict in Gaza continues.

The IDF has long boasted of fighting on multiple fronts, but the long, grim operation against Hamas remains uncompleted and with no obvious plan for a day after. That campaign has also demonstrated the shortfalls in Israeli military thinking – not least the notion that manoeuvre warfare can defeat non-state actors that sometimes behave like conventional forces but can also default to unconventional warfare.

If history has anything to teach us – and following Israel’s past invasions of Lebanon in 1978 (then targeting PLO bases in Operation Litani), in 1985 (leading to an occupation that lasted until 2000), and 2006 – any ground incursion is more likely than not to fall short of its objectives.

OpenAI is reportedly pushing ahead with plans to become a for-profit company, as more senior figures left the ChatGPT developer after the surprise exit of its chief technology officer, Mira Murati.

The San Francisco-based startup is preparing to change its corporate structure as it seeks $6.5bn (£4.9bn) of new funding, according to reports.

Under the changes, OpenAI will become a for-profit benefit corporation – an entity that makes profits but is committed to the social and public good – that will no longer be controlled by its nonprofit board, Reuters reported.

OpenAI declined to comment on the details of the reports but a spokesperson said the nonprofit entity would continue to exist.

“We remain focused on building AI that benefits everyone, and we’re working with our board to ensure that we’re best positioned to succeed in our mission. The nonprofit is core to our mission and will continue to exist,” said the spokesperson.

OpenAI was founded as a nonprofit in 2015 and four years later added a for-profit subsidiary in which Microsoft is the biggest investor. On its website OpenAI describes its structure as “a partnership between our original nonprofit and a new capped profit arm”.

The ChatGPT developer, whose CEO, Sam Altman, has become the poster child for the AI boom, is reportedly heading for a new valuation of $150bn under the new fundraising, broadly in line with Uber’s. Apple and the chipmaker Nvidia are among the companies cited in reports as potential investors in the new funding round.

OpenAI’s progress towards its goal of creating artificial general intelligence – which it describes as “AI systems that are generally smarter than humans” – has alarmed former employees. William Saunders, a research engineer who left OpenAI this year, said he quit because he “lost faith” it would make responsible decisions about AGI, while a former leading safety researcher at the company, Jan Leike, claimed in May that OpenAI was prioritising “shiny products” over safety.

Responding to Leike’s comments on X at the time, Altman wrote: “He’s right we have a lot more to do; we are committed to doing it.”

Reports of the corporate restructuring process, which could run into next year, came as more senior technical staff announced their departures. Murati – who was the figurehead for the May launch of OpenAI’s GPT-4o model – announced on Wednesday she was leaving. She had also spent a short period of time as OpenAI’s temporary CEO in November last year, when Altman was fired and then reinstated by the nonprofit board.

Hours later, two more colleagues, Barret Zoph and Bob McGrew, also quit, according to a post from Altman on social media platform X. Zoph held the title VP research, and McGrew was chief research officer.

“Mira, Bob, and Barret made these decisions independently of each other and amicably, but the timing of Mira’s decision was such that it made sense to now do this all at once, so that we can work together for a smooth handover to the next generation of leadership,” Altman wrote.

He added that leadership changes such as Murati’s departure were a “natural part of companies”, adding: “I obviously won’t pretend it’s natural for this one to be so abrupt, but we are not a normal company.”

Eric Adams, the mayor of New York City, faces charges of accepting bribes and illegal campaign contributions from foreign sources after an indictment was filed against the controversial leader of one of the world’s biggest cities.

In a five-count criminal indictment, US prosecutors allege that before and during his terms as mayor Adams “sought and accepted improper valuable benefits, such as luxury international travel, including from wealthy foreign businesspeople and at least one Turkish government official seeking to gain influence over him”.

The criminal counts against Adam include conspiracy to commit wire fraud and to receive campaign contributions by foreign nationals, wire fraud and solicitation of a contribution by a foreign national.

The complaint focuses on trips Adams and his partner took to Turkey, India and Ghana on Turkish airlines, sometimes staying in luxury hotels, that as an elected official, should have been disclosed to the government and campaign contributions made by Turkish officials through a system of “straw” donors.

Adams “did not disclose the travel benefits he had obtained in annual financial disclosures he was required to file as a New York City employee,” the government alleges. “Sometimes, Adams agreed to pay a nominal fee to create the appearance of having paid for travel that was in fact heavily discounted.”

Prosecutors allege that Adams “created and instructed others to create fake paper trails, falsely suggesting that he had paid, planned to pay, for travel benefits that were free, deleted messages with others involved in his misconduct”.

In September 2021, two months before he was elected New York mayor, prosecutors allege, Turkish officials called in their debt, telling Adams “it was his tum to repay the Turkish Official, by pressuring the New York City Fire Department (‘FDNY) to facilitate the opening of a new Turkish consular building-a 36-story skyscraper without a fire inspection in time for a high-profile visit by Turkey’s president”.

The indictment notes that at the time, the 46-story building close to the UN would have failed an FDNY inspection. “In exchange for free travel and other travel related bribes in 2021 and 2022 arranged by the Turkish Official, Adams did as instructed,” the indictment says.

The moment is a deep crisis for the former cop, who was elected with a tough on crime agenda but who has courted controversy throughout his political career and has been a polarizing figure on the left.

Adams is the first sitting New York City mayor to be criminally charged.

When the news broke of the indictment late on Wednesday night, Adams released a defiant video statement. “I always knew that if I stood my ground for New Yorkers that I would be a target – and a target I became,” Adams said. “If I am charged, I am innocent and I will fight this with every ounce of my strength and spirit.”

He also vowed to stay in office.

“I have been facing these lies for months … yet the city has continued to improve,” Adams said. “Make no mistake. You elected me to lead this city and lead it I will.”

The indictment followed months of scrutiny after some of his closest aides and allies came under federal investigation as prosecutors began examining his inner circle. Less than a month ago federal agents raided the homes of high-ranking officials within Adams’ administration and seized electronic devices from the home of the New York police department commissioner.

More details soon …

The former transit police officer Eric Adams took charge of the largest city in the US in 2022, the second Black person to be elected New York mayor, while the city was still recovering from the disruptions of the Covid pandemic.

At his swearing-in, the cop turned Democratic politico indicated he planned to return some personal panache to a metropolis knocked by a pandemic, political strife and, at times, his unpopular predecessor, Bill de Blasio.

But there were often questions about his career and life, mostly unexplained and sometimes quite strange. In 2011, while serving as a state senator, he had made a video describing how to search for “contraband” – guns, drugs and other illicit paraphernalia – that children may have hidden around the house.

In it, he explained how a jewelry box might actually conceal a firearm and rummaged through the pockets of backpack to find a used crack pipe. Behind a bookshelf there was a giant bag of fake cocaine, along with bullets, a sack of weed and another gun, in odd hiding spots.

There were even questions of whether Adams actually lived in New York with a lot of focus on his owning a property in New Jersey as well as in Brooklyn.

Then there was the question of whether he was vegan, as he repeatedly said he was. The issue came up after he said he was diagnosed with type 2 diabetes in 2016, which he said he was was able to reverse after switching to a whole food, plant-based diet. As mayor, he ordered the city’s public schools to implement “vegan Fridays” and incentivized grocery stores to supply health foods. But the New Yorker magazine also reported that Adams liked to nibble on chicken and others claimed he favored fish when ordering at his favorite restaurant.

On his first day at work, he took the subway to city hall to be at his desk by 8.30am, and held a cabinet meeting half an hour later. Adams presented himself as an non-ideological alternative to De Blasio, one more accustomed to the rhythms of the city, and vowed to improve its relationship with its businesses and to crack down on street and subway crime.

He promised to restore the city’s reputation as the city that never sleeps and dubbed himself the “nightlife mayor”. “I’m just as flexible as the city. I’ll be in New York,” he said. “The 24/7 city that never sleeps. We have heard the alarm clock. We are up now.

“When you’re out at night, it helps decrease crime. It attracts tourists to the city,” he added, saying that every time a New Yorker goes to a restaurant “we’re making sure that a dishwasher, a cook, a bartender and a waiter is employed”.

The mayor’s nocturnal ramblings soon brought unwanted attention. It was reported that he’d visited the Italian restaurant Osteria La Baia – owned by two brothers with past felony convictions – 14 times in a month and had made it his unofficial meeting place. Adams declined to offer proof of who picked up the check.

He employed his younger brother Bernard as head of his security detail, sparking nepotism claims. It was unclear, in the early days of his administration, if he owned a home in the city.

Reports soon began circulating that federal authorities were scrutinizing how city contracts were awarded, including how the Turkish consulate had been quickly cleared to extend its embassy despite concerns by the fire department. Then there were questions about whether the former police commissioner’s twin brother, a nightlife fixer, had profited from insider connections.

Adams was born in the Brownsville section of Brooklyn, and often spoke of his impoverished upbringing. He told how he’d joined the New York City police department in 1984 with the purpose of reforming the force from within after being beaten by cops at age 15.

In 2006, he successfully ran for New York state senate. He was accused of accepting campaign contributions from a politically connected group bidding to bring a casino to a racetrack in Queens. Seven years later, he was elected Brooklyn borough president.

Adams is facing re-election next year and has vowed to become a two-term mayor. But as federal authorities raided his home on Thursday, after weeks of resignations by figures in his administration as federal investigators intensified their probe, that goal may prove elusive.

The city dysfunction that Adams promised to reform had itself visited him, with accompanying federal corruption charges that Adams called “entirely false, based on lies”.

Archaeologists using artificial intelligence (AI) have discovered hundreds of new geoglyphs depicting parrots, cats, monkeys, killer whales and even decapitated heads near the Nazca Lines in Peru, in a find that nearly doubles the number of known figures at the enigmatic 2,000-year-old archaeological site.

A team from the Japanese University of Yamagata’s Nazca Institute, in collaboration with IBM Research, discovered 303 previously unknown geoglyphs of humans and animals – all smaller in size than the vast geometric patterns that date from AD200-700 and stretch across more than 400 sq km of the Nazca plateau.

The new figures, which date back to 200BC, provide a new understanding of the transition from the Paracas culture to the Nazcas, who later created the iconic hummingbird, monkey and whale figures that make up part of the Unesco World Heritage site, Peru’s most popular tourist attraction after Machu Picchu.

“The use of AI in research has allowed us to map the distribution of geoglyphs more quickly and accurately,” said the archaeologist Masato Sakai of Yamagata University, presenting the research at a press conference at the Japanese embassy in Lima on Monday.

The use of AI combined with low-flying drones revolutionised the speed and rate at which the geoglyphs were discovered, according to a research paper published this week in the Proceedings of the National Academy of Sciences (PNAS).

The paper said while it “took nearly a century to discover a total of 430 figurative Nazca geoglyphs”, using an AI system covering the entire Nazca region it “took just six months to discover 303 new figurative geoglyphs”.

The AI model efficiently spotted many of the smaller relief-type geoglyphs which were harder to see with the naked eye.

It was also able to analyse vast quantities of geospatial data generated by drones to identify areas where more geoglyphs might be found.

Johny Isla, Peru’s chief archaeologist for the Nazca Lines, said the use of drones and AI represented a quantum leap for archaeological study in the area.

“With a drone, you can cover several kilometers in a day,” he said by phone from Nazca. “What used to take three or four years, can now be done in two or three days.”

He added that the newly discovered geoglyphs were so small – between three to seven metres across – that they would not have been detected by the flyovers of the past which discovered the giant images, lines and trapezoids that crisscross Nazca’s vast desert plain.

The mysterious lines that attract tens of thousands of tourists every year include a mysterious humanoid figure known as the “astronaut”, animals and vast geometric patterns including perfectly formed spirals and trapezoids which stretch for miles.

The new geoglyphs also differed from Nazca culture’s vast geometric patterns and zoomorphic figures in their meaning, Isla explained.

“We can say that these geoglyphs were made by humans for humans, they often show scenes from everyday life, he said. “Whereas the geoglyphs of the Nazca period are gigantic figures made on mostly flat surfaces to be seen by their gods.”

The older, smaller geoglyphs could have been used as signs, he said, or represented family or kinship groups but probably lacked the ritual significance linked to water and fertility of the larger, latterly drawn lines.

The new figures included large linear geoglyphs, mainly representing wild animals, but they also included gory figures showing humans holding decapitated heads, abstract humanoids and domesticated camelids, such as llamas and alpacas.

Vladimir Putin has escalated his nuclear rhetoric, telling a group of senior officials that Russia would consider using nuclear weapons if it was attacked by any state with conventional weapons.

His remarks on Wednesday came during a meeting with Russia’s powerful security council where he also announced changes to the country’s nuclear doctrine.

The comments marked Russia’s strongest warning yet to the west against allowing Ukraine to launch deep strikes into Russian territory using long-range western missiles.

The Ukrainian president, Volodymyr Zelenskyy, has been asking for months for permission to use British Storm Shadow missiles and US-made Atacms missiles to hit targets deeper inside Russia.

Putin said that Russia would consider using nuclear weapons if Moscow received “reliable information” about the start of a massive launch of missiles, aircraft or drones against it.

Putin also warned that a nuclear power supporting another country’s attack on Russia would be considered a participant in aggression, issuing a thinly veiled threat to the west as foreign leaders continue to mull whether to allow Ukraine to use long-range weapons.

Putin said the clarifications were carefully calibrated and commensurate with the modern military threats facing Russia. “We see the modern military and political situation is dynamically changing and we must take this into consideration. Including the emergence of new sources of military threats and risks for Russia and our allies,” he said.

Zelenskyy’s chief of staff, Andriy Yermak, dismissed the new nuclear doctrine, saying: “Russia no longer has any instruments to intimidate the world apart from nuclear blackmail. These instruments will not work.”

Several influential foreign policy hawks have previously pressed Putin to adopt a more assertive nuclear posture towards the west, lowering its threshold for using nuclear weapons in order to deter the west against providing more direct military support to Ukraine.

The current doctrine was set out by Putin in June 2020 in a six-page decree.

In the early days of Russia’s full-scale invasion of Ukraine, Putin frequently invoked Moscow’s nuclear arsenal, the world’s biggest, repeatedly pledging to use all means necessary to defend Russia.

He later seemed to moderate his rhetoric, but officials close to the Russian president have recently warned Nato countries they risked provoking nuclear war if they gave the green light for Ukraine to use long-range weapons.

Earlier this month, Putin said that the west would be directly fighting with Russia if it gave such permission to Ukraine – and that Russia would be forced to make “appropriate decisions”, without spelling out what those measures could be.

Vladimir Putin has escalated his nuclear rhetoric, telling a group of senior officials that Russia would consider using nuclear weapons if it was attacked by any state with conventional weapons.

His remarks on Wednesday came during a meeting with Russia’s powerful security council where he also announced changes to the country’s nuclear doctrine.

The comments marked Russia’s strongest warning yet to the west against allowing Ukraine to launch deep strikes into Russian territory using long-range western missiles.

The Ukrainian president, Volodymyr Zelenskyy, has been asking for months for permission to use British Storm Shadow missiles and US-made Atacms missiles to hit targets deeper inside Russia.

Putin said that Russia would consider using nuclear weapons if Moscow received “reliable information” about the start of a massive launch of missiles, aircraft or drones against it.

Putin also warned that a nuclear power supporting another country’s attack on Russia would be considered a participant in aggression, issuing a thinly veiled threat to the west as foreign leaders continue to mull whether to allow Ukraine to use long-range weapons.

Putin said the clarifications were carefully calibrated and commensurate with the modern military threats facing Russia. “We see the modern military and political situation is dynamically changing and we must take this into consideration. Including the emergence of new sources of military threats and risks for Russia and our allies,” he said.

Zelenskyy’s chief of staff, Andriy Yermak, dismissed the new nuclear doctrine, saying: “Russia no longer has any instruments to intimidate the world apart from nuclear blackmail. These instruments will not work.”

Several influential foreign policy hawks have previously pressed Putin to adopt a more assertive nuclear posture towards the west, lowering its threshold for using nuclear weapons in order to deter the west against providing more direct military support to Ukraine.

The current doctrine was set out by Putin in June 2020 in a six-page decree.

In the early days of Russia’s full-scale invasion of Ukraine, Putin frequently invoked Moscow’s nuclear arsenal, the world’s biggest, repeatedly pledging to use all means necessary to defend Russia.

He later seemed to moderate his rhetoric, but officials close to the Russian president have recently warned Nato countries they risked provoking nuclear war if they gave the green light for Ukraine to use long-range weapons.

Earlier this month, Putin said that the west would be directly fighting with Russia if it gave such permission to Ukraine – and that Russia would be forced to make “appropriate decisions”, without spelling out what those measures could be.

Donald Trump’s mass voter turnout program in crucial battleground states is now largely outsourced to America Pac, the political action committee backed by the billionaire Elon Musk, according to multiple people familiar with the situation.

The Trump campaign gambled with its general field operation for the 2024 cycle and outsourced it to Super Pacs, while it targeted its focus on turning out Trump supporters in rural areas who typically do not vote.

But while the Trump campaign once predicted having multiple Pacs drive the rest of the vote, with six weeks until the election, only America Pac has a material presence of 300 to 400 paid and part-time people knocking on doors in each of the seven battleground states.

America Pac also remains the only entity – Trump campaign or otherwise – with a target to do three “passes” of homes of likely Trump voters in every battleground state before election day.

Turning Point Action, run by the rightwing activist Charlie Kirk and touted by the Trump campaign, for instance, has a smaller footprint; it has a presence in Arizona, Wisconsin and two specific districts in Michigan and Nevada, after dropping Georgia from its initial list.

The situation means America Pac now accounts for an outsize proportion of the unglamorous but critical work of door-knocking and canvassing Trump voters in battleground states to get them to return a ballot.

Since the Trump campaign does not have its own mass field program – it has a new model of “Trump 47 Captains”, volunteers targeting likely Trump supporters who do not typically vote – the campaign has little backup if America Pac hits snags.

Last week, America Pac fired the company it had retained in Arizona and Nevada to do door-knocking and canvassing.

The move to terminate the September Group had damaging consequences for Trump as America Pac lost several days of canvassing while they sought a replacement company, and lost at least some of the roughly 300 people they hired in each state.

The Trump campaign denied that it had a reliance on America Pac and said it had more than 27,000 volunteers working as Trump 47 Captains, the program in which ardent Trump supporters receive special Maga merchandise as they get more people to register to vote.

Each volunteer initially receives a list of 10 neighbors to mobilize. If they meet that target, the next tier involves canvassing 24 out of 50 likely Trump voters, followed by canvassing 45 out of 100 voters, with new perks at each tier.

“Team Trump has hundreds of staff and offices mobilizing hundreds of thousands of volunteers across the country. That’s why everyone wants to take credit for our groundbreaking, data-enhanced, people-powered operation,” Karoline Leavitt, a Trump spokesperson, said in a statement.

But a person involved with America Pac expressed skepticism about the reach of the Trump 47 captains and noted targeting just so-called low propensity voters in rural areas is no substitute for hitting doors in suburban areas and cities as well.

Separately, if Trump wins, it could be in part thanks to Musk, who has articulated wider political ambitions – he recently pitched to Trump to serve in his cabinet in a second term – and resultantly have outsized influence with Trump.

The America Pac operation was slow to get started after it scrapped its initial plans, and only started hiring employees at a rapid clip last month.

But it has since exploded in size. By retaining canvassing vendors for each battleground state, America Pac’s operation now involves hundreds of paid and part-time employees to knock on doors in an unusually aggressive get-out-the-vote effort, the person said.

In North Carolina and Michigan, America Pac’s vendor, Blitz Canvassing LLC, has hired more than 400 staffers in each state, the person said. America Pac has paid roughly $3.3m to Blitz to date, according to federal campaign finance filings.

Blitz is now also responsible for Arizona and Nevada after it was named as the successor to the September Group. It has a mandate to rehire as many of the fired 300 canvassers as possible, and in Nevada, to hit roughly 30,000 doors a day.

The retention of Blitz has been controversial inside Trump world, in part because Blitz is a subsidiary of a company called GP3 owned by the political consultants running America Pac. It has given rise to accusations that America Pac’s leadership is profiting twice.

For Pennsylvania and Georgia, America Pac has subcontracted to Patriot Grassroots LLC and paid about $2.3m to date. For Wisconsin, America Pac has subcontracted to the Synapse Group for about $468,000, according to campaign finance filings.

Italy has reinstated a measure to fail badly behaved pupils as concerns grow over aggression directed at teachers.

The “grades for conduct” policy, similar to a measure first introduced by Benito Mussolini’s fascist government in 1924, is part of an education bill that was approved in parliament on Wednesday, and gives schools the power to fail students based purely on their behaviour.

Middle school and high school pupils who score five or less out of 10 on conduct will fail the year and face having to repeat it even if their academic standard is up to par. High school students who only score six on conduct will have to do a civic education test. Marks in behaviour will also greatly influence the sitting of the crucial maturità school-leaving exam.

Giuseppe Valditara, the education minister in Giorgia Meloni’s far-right government, said: “The grades-for-conduct reform restores the importance of individual responsibility, makes respect of people and public goods central and restores the authoritativeness of teachers.” Meloni has previously said the change would “bring back respect” in schools.

Fines of between €500 (£415) and €10,000 have been introduced for acts of aggression or violence towards school staff.

The law, embraced by ANP, Italy’s association of headteachers, follows a more than 110% rise in aggressive incidents towards teaching staff since the beginning of the year compared with 2023. In many cases teachers have needed medical treatment, while in others the perpetrators were the pupils’ parents. Students often clash with their teachers over the use of mobile phones in class.

Antonello Giannelli, the ANP president, said the measure was “a step forward”. “We have heard of too many cases of undisciplined and out-of-the-ordinary behaviour,” he said. “It is right that students are called to reflect on their responsibilities as a consequence of their actions.”

Tommaso Martelli, the coordinator of a national student union, said the move was aimed at “reinforcing an authoritarian and punitive culture”. “The possibility of being failed for violations of the rules now makes the grades for conduct measure something that can be used as a further repressive tool in our schools,” he said.

The original Mussolini-era measure remained in place until the mid-1970s, before it was scrapped in elementary and middle schools after student protests. It underwent modifications over the years before being removed in all schools in 2000.

The package of measures, already approved in the senate, passed in the lower house with 154 votes in favour, 97 against and seven abstentions.

Anna Ascani, a politician with the centre-left Democratic party, said the conduct rule marked “a return to a time that we would prefer to forget”.

A 20-year-old man tossed an explosive device into the California courthouse where he was about to be arraigned on a gun charge and the explosion left five people with minor injuries and shut down the court complex and other nearby city buildings, police said.

The explosion occurred on Wednesday morning in Santa Maria, a city of about 110,000 in California’s central coast region. The suspect ran away after the explosion and was captured as he tried to get into his vehicle parked nearby.

The man, who is from Santa Maria, was wearing body armor underneath his jacket, according to Santa Barbara county undersheriff, Craig Bonner, and was booked on attempted murder and explosives charges. Officials are also investigating whether the suspect is tied to a series of recent arsons.

Officials said it appeared the courthouse attack was related to his earlier arrest on a gun possession charge and was not terrorism or an act of political violence.

“We do believe this is a local matter that has been safely resolved and that there are no outstanding community safety concerns,” Bonner said.

The suspect had been arrested last July for illegal gun possession and was to be arraigned on Wednesday. When he entered the courthouse and approached the screening station he tossed a bag that then detonated.

Bonner said three of the five victims suffered burns. All were treated and released from a hospital. None were court employees.

Authorities evacuated a five-block radius of businesses, homes and a school after the explosion. The courthouse will be closed on Thursday as police complete their investigation, and filing extensions will be offered for those affected by the shutdown.

Shane Mellon told KSBY-TV he was at the courthouse when he heard what sounded like chairs falling over.

“It was a loud bang,” he said, adding the bailiff escorted him and others out.

Mellon said he saw what looked like a sweater smoldering and a man screaming while four or five people got on top of him, trying to keep him restrained.

“I think this could have been way worse than it was if not for the deputies just jumping on top of that guy,” Mellon said.

Santa Maria is about 150 miles (240km) north-west of Los Angeles. The courthouse, which houses state and county courtrooms, was where Michael Jackson was tried and acquitted of sexual abuse two decades ago.

A bizarre type of fish with leg-like appendages uses its limbs not only to scurry around but also for “tasting” the sea floor to find buried prey, researchers have found.

Sea robins have six leg-like structures that are formed from modified fins and are known to use them to walk across the sea floor and even flip over shells in a hunt for prey.

Researchers have long suspected their legs could also help the fish to detect food in others ways, and now scientists in the US have released two studies revealing the genes that give rise to the sea robins’ legs and also how such limbs are used.

Writing in the journal Current Biology, the team report how they placed individual sea robins into tanks containing water and sand. Buried beneath the sand were either mussels, capsules containing mussel extract, or capsules containing seawater.

The team found that a species known as Prionotus carolinus regularly turned up all of the prey-related items but not the seawater capsules.

Further work revealed that nerves in the limbs of these fish fired when the legs were exposed to various food-related chemicals, such as amino acids, while the sea robins could locate buried capsules containing such substances.

The team found that the ability of the fish to locate mussels decreased with the depth at which the molluscs were buried, as would be expected if the sea robins were using their limbs to detect chemicals released by the prey.

In addition, the researchers found that the legs of these sea robins were covered in small bumps similar to those seen on a human tongue, and the bumps bore taste receptors. The researchers suggest that the bumps could boost both touch and chemical sensitivity.

Dr Corey Allard, a co-author of the research from Harvard University, said: “It’s like they’ve repurposed some of the machinery used in taste, but in a very different way, and for a very different reason.”

The team found another species of sea robin known as Prionotus evolans did not dig and failed to find buried prey, while the nerves in its legs did not respond to the same suite of food-related chemicals, and the limbs were not covered in bumps.

By studying other species of sea robin, the team suggested that the creatures’ legs were initially used for motion, and that other properties – such as greater sensitivity and ability to taste – cropped up later in evolution.

Allard said sea robins could offer scientists an opportunity to study how new body parts emerge during evolution and novel traits form, as well as how brains evolve and adapt to such changes.

He said: “These crazy little weird fish have a lot of things to tell us that we probably couldn’t learn from a more conventional research organism like a mouse.”

If exercise takes a back seat in the working week, take heart. Cramming the recommended amount of physical activity into the weekend still has significant health benefits, research suggests.

A study of nearly 90,000 people enrolled in the UK Biobank project found that “weekend warriors” who fit a week’s worth of exercise into one or two days had a lower risk of developing more than 200 diseases compared with inactive people.

Scientists followed people’s health for years after monitoring their exercise patterns and saw reduced risks across the full spectrum of human disease, from hypertension and diabetes to mood disorders and kidney disease.

The more concentrated bouts of physical activity favoured by weekend warriors seemed as effective at reducing the risk of future disease as regular sessions spread evenly through the week, leading researchers to suspect the total amount of exercise people got was more important than how frequently they trained.

“I think this is empowering,” said Dr Shaan Khurshid, a cardiologist at Massachusetts general hospital in Boston, who led the study. “It shows that, in terms of health benefits, it’s really the volume of physical activity rather than the pattern that matters. The key is, however you are going to get that volume, do it in the way that works for you.”

The NHS recommends 150 minutes of moderate exercise or 75 minutes of vigorous exercise a week to keep healthy, with even one or two sessions a week reducing the risk of heart disease and stroke. As a rule of thumb, the border between moderate and vigorous exercise is when it becomes too difficult to finish spoken sentences while exercising.

Writing in Circulation, the researchers describe how they analysed health records of 89,573 UK Biobank volunteers who, as part of the project, had worn a device on their wrist to measure their exercise patterns for a week.

Those who managed at least 150 minutes of moderate to vigorous exercise were classed as regular exercisers if their physical activity was spread out, and weekend warriors if most of their exercise was crammed into one or two days. Those who did fewer than 150 minutes a week were classed as inactive.

In the years after wearing the exercise monitor, weekend warriors had a lower risk of 264 medical conditions compared with those deemed inactive. The regular exercisers experienced similar benefits.

The strongest effects were for cardiometabolic disorders. Compared with inactive people, the risk of hypertension was more than 20% lower in weekend warriors and regular exercisers, while the risk of diabetes was down more than 40%.

Previous studies have reported similar findings. In 2017, Gary O’Donovan, a physical activity researcher then at Loughborough University, found that weekend warriors and regular exercisers who met physical activity targets were less likely to die from cancer or cardiovascular conditions than sedentary people. Another study, in 2022, echoed the benefits.

One question that hangs over such observational studies is whether exercise is really preventing disease, or whether healthier people, who have a lower risk of disease already, simply exercise more. Both are likely to be at work. In the latest study, the researchers tried to address this by ruling out people who developed medical conditions within two years of exercise monitoring.

Khurshid said further studies were needed to explore whether concentrated bouts of exercise could help people meet physical activity targets more easily. “It might be more convenient for some people, it might increase adherence to public health interventions,” he said.

Dr Leandro Rezende, an expert in preventive medicine at the Federal University of São Paulo, who led the 2022 study into health and exercise, said: “These findings confirm that total volume matters most, regardless of the weekly frequency.

“This is good news for those trying to reach the World Health Organization guidelines and have only a few days a week to do so. However, it is important to consider that, for those who are already reaching the guidelines, increasing the frequency may help to increase the total volume of physical activity and therefore obtain further health benefits.”