A giant planet 124 light years from Earth has yielded the strongest evidence yet that extraterrestrial life may be thriving beyond our solar system, astronomers claim.

Observations by the James Webb space telescope of a planet called K2-18 b appear to reveal the chemical fingerprints of two compounds that, on Earth, are only known to be produced by life.

Detection of the chemicals, dimethyl sulfide (DMS) and dimethyl disulfide (DMDS) would not amount to proof of alien biological activity, but could bring the answer to the question of whether we are alone in the universe much closer.

“This is the strongest evidence to date for a biological activity beyond the solar system,” said Prof Nikku Madhusudhan, an astrophysicist at the University of Cambridge who led the observations. “We are very cautious. We have to question ourselves both on whether the signal is real and what it means.”

He added: “Decades from now, we may look back at this point in time and recognise it was when the living universe came within reach. This could be the tipping point, where suddenly the fundamental question of whether we’re alone in the universe is one we’re capable of answering.”

Others are more sceptical, with questions remaining about whether the overall conditions on K2-18 b, are favourable to life and whether DMS and DMDS, which are largely produced by marine phytoplankton on Earth, can be reliably regarded as biosignatures.

K2-18 b, which sits in the Leo constellation, is nearly nine times as massive as the Earth and 2.6 times as large and orbits in the habitable zone of its star, a cool red dwarf less than half the size of the sun. When the Hubble space telescope appeared to spot water vapour in its atmosphere in 2019, scientists declared it “the most habitable known world” beyond the solar system.

The supposed water signal was shown to be methane in follow-up observations by Madhusudhan’s team in 2023. But, they argued, K2-18 b’s profile was consistent with a habitable world, covered in a vast, deep ocean – a view that remains contentious. More provocatively, the Cambridge team reported a tentative hint of DMS.

Planets beyond our solar system are too distant to photograph or reach with robotic spacecraft. But scientists can estimate their size, density and temperature and probe their chemical makeup by tracking the exoplanet as it passes across the face of its host star and measuring starlight that has been filtered through its atmosphere. In the latest observations, wavelengths that are absorbed by DMS and DMDS, were seen to suddenly drop off as K2-18 b wandered in front of the red dwarf.

“The signal came through strong and clear,” said Madhusudhan. “If we can detect these molecules on habitable planets, this is the first time we’ve been able to do that as a species … it’s mind-boggling that this is possible.”

The findings, published in The Astrophysical Journal Letters, suggest concentrations of DMS, DMDS or both (their signatures overlap) thousands of times stronger than the levels on Earth. The results are reported with a “three-sigma” level of statistical significance (a 0.3% probability that they occurred by chance) although this falls short of the gold standard for discoveries in physics.

“There may be processes that we don’t know about that are producing these molecules,” Madhusudhan said. “But I don’t think there is any known process that can explain this without biology.”

A challenge in identifying potential other processes is that the conditions on K2-18 b remain disputed. While the Cambridge team favour an ocean scenario, others say the data is suggestive of a gas planet or one with oceans made of magma, not water.

There is a question of whether DMS could have been brought to the planet by comets – this would require an intensity of bombardment that seems improbable – or produced in hydrothermal vents, volcanoes or lightning storms through exotic chemical processes.

“Life is one of the options, but it’s one among many,” said Dr Nora Hänni, a chemist at the Physics Institute of the University of Berne, whose research revealed that DMS was present on an icy, lifeless comet. “We would have to strictly rule out all the other options before claiming life.”

Others say that measuring planetary atmospheres may never yield a smoking gun for life. “It’s under-appreciated in the field, but technosignatures, such as an intercepted message from an advanced civilisation, could be better smoking guns, despite the unlikelihood of finding such a signal,” said Dr Caroline Morley, an astrophysicist at the University of Texas, Austin, adding that the findings were, nonetheless, an important advance.

Dr Jo Barstow, a planetary scientist at the Open University, also viewed the detection as significant, but said: “My scepticism dial for any claim relating to evidence of life is permanently turned up to 11, not because I don’t think that other life is out there, but because I feel that for such a profound and significant discovery the burden of proof must be very, very high. I don’t think this latest work crosses that threshold.”

At 120 light years away, there is no prospect of resolving the debate through closeup observations, but Madhusudhan notes that this has not been a barrier to the discovery of black holes or other cosmic phenomena.

“In astronomy, the question is never about going there,” he said. “We’re trying to establish if the laws of biology are universal in nature. I don’t see it as: ‘We have to go and swim in the water to catch the fish.’”

Prime Minister Mark Carney said the key question in Canada’s upcoming election is who is best to deal with Donald Trump as he faced his Conservative rival in a French-language leaders’ debate on Wednesday.

Opposition Conservative leader Pierre Poilievre said during the debate Canada needs change after a decade of Liberal party rule and Carney is just like his predecessor, Justin Trudeau. Carney responded: “Mr Poilievre is not Justin Trudeau. I’m not Justin Trudeau either. In this election the question is who is going to face Mr Trump.”

The exchange was the first between the two men since Carney was elected Liberal leader in March.

Trump’s trade war and threats to make Canada the 51st state have infuriated Canadians and led to a surge in Canadian nationalism that has bolstered Carney’s Liberal party poll numbers ahead of the 28 April vote.

The debate took place in Montreal, the largest city in predominantly French-speaking Quebec. The province has 78 of the 343 seats in the House of Commons and is usually regarded as one of the keys to victory.

Poilievre is imploring Canadians not to give the Liberals a fourth term. He hoped to make the election a referendum on Trudeau, whose popularity declined toward the end of his decade in power as food and housing prices rose and immigration surged.

But Trump attacked, Trudeau resigned and Carney, a two-time central banker, became Liberal party leader and prime minister after a party leadership race.

When asked about Trudeau at a news conference after the debate, Carney said: “One of the differences, there are many, but one of the differences between the two of us is that I put much more emphasis on the economy, on growing the economy.

“In fact in this circumstance that we are in, given the scale of the crisis, I would say relentless focus on growing the economy.”

Yves-François Blanche of the separatist Bloc Québécois, whose party is losing support to Carney’s Liberals in Quebec, agreed with the Conservatives’ call for change, saying the Liberals are the same party, the same ministers and the same lawmakers and a new leader does not change that.

But public opinion too has changed. In a mid-January poll by Nanos, Liberals trailed the Conservative party by 47% to 20%. In the latest Nanos poll released on Wednesday, the Liberals led by eight percentage points. The January poll had a margin of error 3.1 points while the latest poll had a 2.7-point margin.

The French debate was moved up by two hours to minimise a conflict with a Montreal Canadiens hockey game. The NHL team faced off against the Carolina Hurricanes at 7pm ET, in a game that could clinch them a spot in the Stanley Cup playoffs.

This isn’t the first time NHL hockey has elbowed its way onto the campaign trail. During the 2011 election, former Bloc leader Gilles Duceppe asked for a debate to be postponed due to a Canadiens hockey game, and his request was granted.

The English language debate is being held on Thursday evening.

With Associated Press and Reuters

Maryland’s Democratic senator Chris Van Hollen says the government of El Salvador has denied his request to visit Kilmar Ábrego García, his constituent who was wrongly deported to the Central American country last month.

Van Hollen traveled to El Salvador on Wednesday with the intention of meeting Ábrego García at the Terrorism Confinement Center (Cecot), where US authorities have said that the Maryland resident is being held along with others deported at Donald Trump’s orders.

The senator’s visit came days after Trump and El Salvador’s president, Nayib Bukele, refused to take steps to return Ábrego García to the United States, even though the US supreme court last week said the administration must “facilitate” his return.

At a press conference in El Salvador, Van Hollen said that he had met with the country’s vice-president, Félix Ulloa, who told him it would not be possible for him to speak with Ábrego García in person or on the phone.

“I asked the vice-president if I could meet with Mr Ábrego García. And he said, well, you need to make earlier provisions to go visit Cecot,” Van Hollen said. “I said, I’m not interested at this moment in taking a tour of Cecot, I just want to meet with Mr Ábrego García. He said he was not able to make that happen.”

Van Hollen said he offered to come back next week to meet with Ábrego García, but Ulloa “said he couldn’t promise that either”. The vice-president also said he could not arrange for Ábrego García’s family to speak to him by phone. When the senator asked if he could do so, Ulloa told him that the US embassy must make that request, Van Hollen said.

“We have an unjust situation here. The Trump administration is lying about Ábrego García,” said Van Hollen, who said his constituent had been wrongly named as a member of the MS-13 criminal gang. The Trump administration has admitted that an “administrative error” led to the deportation of Ábrego García to his native country, despite an immigration judge granting him protected status in 2019.

Van Hollen said that he had asked Ulloa if he would consider releasing Ábrego García, to which the vice-president replied by reiterating Bukele’s comments from earlier this week that he would not “smuggle” the deportee back into the United States.

The senator’s visit came as Democrats have seized on the deportation and the Trump administration’s refusal to take any steps to return him, in apparent defiance of the supreme court, to argue that the president is plunging the United States into a constitutional crisis by defying the courts.

The White House has attacked Van Hollen for his visit to the country, releasing a statement on Wednesday that touted the arrests of suspected undocumented immigrant criminals and saying: “Where was his concern for Maryland constituents put at risk by the many other illegal immigrants allowed to roam free until now?”

In an appearance on Fox News, Trump’s border czar, Tom Homan, said: “Rather than taking care of the constituents in his state, the victims of illegal crime in his state, he’s going to run to El Salvador to protect an MS-13 terrorist. It’s just disgusting.”

Several other Democratic lawmakers have signaled that they would like to visit El Salvador to check on Ábrego García, including Adriano Espaillat, chair of the Congressional Hispanic caucus, and Robert Garcia and Maxwell Alejandro Frost, both members of the House oversight committee.

“I can assure the president, the vice-president, that I may be the first United States senator to visit El Salvador on this issue, but there will be more and there will be more members of Congress coming,” Van Hollen said.

“This is an unsustainable and unjust moment, and so it cannot continue this way.”

A federal judge ruled on Wednesday that there was probable cause to hold Trump officials in criminal contempt for violating his temporary injunction that barred the use of the Alien Enemies Act wartime power to deport alleged Venezuelan gang members.

In a scathing 46-page opinion, James Boasberg, the chief US district judge for Washington, wrote that senior Trump officials could either return the people who were supposed to have been protected by his injunction, or face contempt proceedings.

The judge also warned that if the administration tried to stonewall his contempt proceedings or instructed the justice department to decline to file contempt charges against the most responsible officials, he would appoint an independent prosecutor himself.

“The court does not reach such conclusions lightly or hastily,” Boasberg wrote. “Indeed, it has given defendants ample opportunity to explain their actions. None of their responses have been satisfactory.”

The threat of contempt proceedings marked a major escalation in the showdown over Donald Trump’s use of the Alien Enemies Act of 1798 to deport alleged Venezuelan gang members, without normal due process, in his expansive interpretation of his executive power.

It came one day after another federal judge, in a separate case involving the wrongful deportation of a man to El Salvador, said she would force the administration to detail what steps it had taken to comply with a US supreme court order compelling his return.

In that case, US district judge Paula Xinis ordered the administration to answer questions in depositions and in writing about whether it had actually sought to “facilitate” the return of Kilmar Ábrego García, who was protected from being sent to El Salvador.

Taken together, the decisions represented a developing effort by the federal judiciary to hold the White House accountable for its apparent willingness to flout adverse court orders and test the limits of the legal system.

At issue in the case overseen by Boasberg is the Trump administration’s apparent violation of his temporary restraining order last month blocking deportations under the Alien Enemies Act – and crucially to recall planes that had already departed.

The administration never recalled the planes and argued, after the fact, that they did not follow Boasberg’s order to recall the planes because he gave that instruction verbally and it was not included in his later written order.

In subsequent hearings, lawyers for the Trump administration also suggested that even if Boasberg had included the directive in his written order, by the time he had granted the temporary restraining order, the deportation flights were outside US airspace and therefore beyond the judge’s jurisdiction.

Boasberg excoriated that excuse and others in his opinion, writing that under the so-called collateral-bar rule, if a party is charged with acting in contempt for disobeying a court order, it cannot raise the possible legal invalidity of the order as a defense.

“If Defendants believed – correctly or not – that the Order encroached upon the President’s Article II powers, they had two options: they could seek judicial review of the injunction but not disobey it, or they could disobey it but forfeit any right to raise their legal argument as a defense,” Boasberg wrote.

Boasberg also rejected the administration’s claim that his authority over the planes disappeared the moment they left US airspace, finding that federal courts regularly restrain executive branch conduct abroad, even when it touches on national security matters.

“That courts can enjoin US officials’ overseas conduct simply reflects the fact that an injunction … binds the enjoined parties wherever they might be; the ‘situs of the [violation], whether within or without the United States, is of no importance,’” Boasberg wrote.

Boasberg added he was unpersuaded by the Trump administration’s efforts to stonewall his attempts to date to establish whether it knew it had deliberately flouted his injunction, including by invoking the state secrets doctrine to withhold basic information about when and what times the planes departed.

“The Court is skeptical that such information rises to the level of a state secret. As noted, the Government has widely publicized details of the flights through social media and official announcements thereby revealing snippets of the information the Court seeks,” Boasberg wrote.

Two of Donald Trump’s top national security aides will hold talks in Paris on Thursday with European politicians and security advisers, as the US and Europe search for common ground on ending the Ukraine war and averting an Iran conflict.

The US secretary of state, Marco Rubio, and special envoy to the Middle East, Steve Witkoff, are expected to hear concerns about Russia amid so-far fruitless US attempts to arrange a ceasefire three years after Russia invaded its neighbour.

Rubio and Witkoff will meet the French president, Emmanuel Macron, as well as British and German figures, including the UK foreign secretary, David Lammy.

The US president’s frustration with Russia and Ukraine over the war has been increasing and he has been threatening military action against Iranian nuclear facilities.

European leaders have grown more concerned as Trump has heaped pressure and criticism on Ukraine’s president, Volodymyr Zelenskyy, while instead making diplomatic gestures to the Russian president, Vladimir Putin.

The Polish foreign minister, Radosław Sikorski, said on Monday that he hoped Trump and his administration would see that Putin was “mocking their goodwill” after Moscow’s deadly missile strike on the Ukrainian city of Sumy.

No specific proposals for the talks have been made public.

France, Britain and Germany were surprised by Trump opening discussions on improving ties with Russia, but have sought a coordinated European response to protecting Ukraine during the conflict and in any ceasefire.

Britain and France have proposed a mainly European “reassurance” force prepared to go to Ukraine if a ceasefire starts. However, many European leaders say it would need US support.

Besides Macron, the French foreign ministry said Rubio would also meet his French counterpart, Jean-Noël Barrot, to discuss Ukraine, prospects for a new Iran nuclear deal and the Middle East.

Witkoff plans to fly on to Rome for a second round of discussions on Saturday with the Iranian foreign minister, Abbas Araghchi, about Iran’s nuclear programme. They met for 45 minutes in Oman on Saturday. Both sides described those talks as positive while acknowledging any potential deal remained distant.

Trump said on Monday he was willing to bomb Iran’s nuclear facilities if a deal was not reached.

On Tuesday, he held a meeting with top national security advisers at the White House focused on Iran’s nuclear programme, according to sources familiar with the encounter.

The US had not told European countries about the nuclear talks in Oman before Trump announced them, even though they hold a key card on the possible reimposition of UN sanctions on Tehran.

Thursday’s talks will be an opportunity for potential coordination between US and Europe.

Trump has restored a “maximum pressure” campaign on Tehran since February after ditching a 2015 nuclear pact between Iran and six world powers during his first term and reimposed crippling sanctions on the Islamic republic.

Trump said on Monday he believed Iran was intentionally delaying a nuclear deal with the US and that it must abandon any drive for a nuclear weapon or face a possible military strike on atomic facilities.

With Reuters

Michelle Trachtenberg, a popular TV actor, died of complications from diabetes, according to the New York City medical examiner’s office.

Trachtenberg, 39, was found dead in February and had recently received a liver transplant, according to NBC News, but the cause of her death had been unclear at the time.

Trachtenberg rose to fame at a young age, starting her career at the age of three when she starred in commercials before going on to join Nickelodeon’s show The Adventures of Pete & Pete, as well as the soap opera All My Children.

The actor landed her first lead film role in the 1996 film Harriet the Spy, acting alongside Rosie O’Donnell and J Smith-Cameron. Speaking to Entertainment Tonight in 2021, Trachtenberg said: “There was a lot required of me … I’m extremely grateful for the opportunity.”

Other projects Trachtenberg starred in include the teen comedy EuroTrip, as well as the critically acclaimed drama Mysterious Skin by Gregg Araki.

Reflecting on her experience with Mysterious Skin, Trachtenberg said: “I was this girl who had done glitzy, PG-themed stuff and here’s Gregg Araki, director of Doom Generation, and we sat down and had a cup of coffee and I said: ‘You’re probably not gonna hire me but this is what I got, this is what I feel. If you’re willing to take the chance, I’m willing to go there with you.’ It was the most exhilarating experience I’ve had as an actress.”

Following her death, Trachtenberg’s various cast members paid tributes to her, with her Gossip Girl co-star Blake Lively writing: “She was electricity … You knew when she entered a room because the vibration changed. Everything she did, she did 200%.”

Similarly, Smith-Cameron wrote: “She was always very warm toward me. I feel very shocked and unsettled to hear of her passing.”

Meanwhile, the Buffy the Vampire lead, Sarah Michelle Gellar, said: “Michelle, listen to me … Listen. I love you. I will always love you. The hardest thing in this world, is to live in it. I will be brave. I will live … for you.”

Michelle Trachtenberg, a popular TV actor, died of complications from diabetes, according to the New York City medical examiner’s office.

Trachtenberg, 39, was found dead in February and had recently received a liver transplant, according to NBC News, but the cause of her death had been unclear at the time.

Trachtenberg rose to fame at a young age, starting her career at the age of three when she starred in commercials before going on to join Nickelodeon’s show The Adventures of Pete & Pete, as well as the soap opera All My Children.

The actor landed her first lead film role in the 1996 film Harriet the Spy, acting alongside Rosie O’Donnell and J Smith-Cameron. Speaking to Entertainment Tonight in 2021, Trachtenberg said: “There was a lot required of me … I’m extremely grateful for the opportunity.”

Other projects Trachtenberg starred in include the teen comedy EuroTrip, as well as the critically acclaimed drama Mysterious Skin by Gregg Araki.

Reflecting on her experience with Mysterious Skin, Trachtenberg said: “I was this girl who had done glitzy, PG-themed stuff and here’s Gregg Araki, director of Doom Generation, and we sat down and had a cup of coffee and I said: ‘You’re probably not gonna hire me but this is what I got, this is what I feel. If you’re willing to take the chance, I’m willing to go there with you.’ It was the most exhilarating experience I’ve had as an actress.”

Following her death, Trachtenberg’s various cast members paid tributes to her, with her Gossip Girl co-star Blake Lively writing: “She was electricity … You knew when she entered a room because the vibration changed. Everything she did, she did 200%.”

Similarly, Smith-Cameron wrote: “She was always very warm toward me. I feel very shocked and unsettled to hear of her passing.”

Meanwhile, the Buffy the Vampire lead, Sarah Michelle Gellar, said: “Michelle, listen to me … Listen. I love you. I will always love you. The hardest thing in this world, is to live in it. I will be brave. I will live … for you.”

Temu and Shein are cutting back their spending on US social media advertising as they lose an exemption on tariffs for many of their shipments from China and Hong Kong.

The online e-tailers, both of which ship low-priced China-made goods direct to US shoppers, had been on an ad spree until recently. But under an executive order from Donald Trump, as of 2 May their sales valued at under $800 will no longer be exempt from US tariffs.

Temu and Shein plan to raise product prices next week as the removal of this “de minimis” exemption increases their costs. They are cutting ad spending on most platforms, according to two digital marketing firms.

Temu’s daily average US ad spend on Facebook, Instagram, TikTok, Snap, X and YouTube declined a collective average of 31% in the two weeks from 31 March to 13 April compared with the previous 30 days, said Sensor Tower.

Shein’s daily average US ad spend on Facebook, Instagram, TikTok, YouTube and Pinterest fell a collective average of 19% over the same period.

Mark Ballard, director of digital marketing research at Tinuiti, said Temu had sharply reduced ads on Google Shopping since 12 April.

Meta declined to comment while Google, Shein and Temu were not immediately available for comment.

With Reuters

The doctor who carried out the postmortems of the 15 paramedics and rescue workers who were killed by Israeli troops in Gaza in March has said they were mostly killed by gunshots to the head and torso, as well as injuries caused by explosives.

There was international outcry last month after it emerged that Israeli troops had launched a deadly attack on a group of paramedics from the Palestinian Red Crescent, civil defence and United Nations workers, as they carried out a rescue operation in southern Gaza.

Their bodies, along with the crushed vehicles, were buried in a sandy mass grave in Gaza by Israeli troops. After digging up the bodies days later, the UN claimed they had been executed “one by one”.

Ahmed Dhair, the forensic pathologist in Gaza who carried out autopsies on 14 out of the 15 victims, told the Guardian he had found “lacerations, entry wounds from bullets, and wounds resulting from explosive injuries. These were mostly concentrated in the torso area – the chest, abdomen, back, and head.”

Most had died from gunshot wounds, including what Dhair said was evidence of “explosive bullets”, otherwise known as “butterfly bullets”, which explode in the body upon impact, ripping apart flesh and bone.

“We found remains of explosive bullets,” said Dhair. “In one case, the bullet head had exploded in the chest, and the rest of the bullet fragments were found within the body. There were also remnants or shrapnel from bullets scattered on the back of one of the victims.”

The Israel Defense Forces (IDF) did not immediately respond to allegations that these bullets had been used in the attack.

Details of the incident have remained disputed. Video footage that emerged from the beginning of the attack shows the convoy of ambulances coming under fire, but the subsequent events that led to the bodies of 15 workers being buried in a mass grave are still unclear.

Israel’s military admitted carrying out the killings but was forced to change its version of events after evidence emerged that contradicted its account that the vehicles had been “moving suspiciously” without lights.

Israel has claimed, without publicly presenting evidence, that six of the unarmed workers killed were Hamas operatives, which has been denied by Red Crescent.

Dhair said his findings did not suggest the paramedics had been shot at close range, but emphasised he was not a munitions expert. He said the shrapnel found in the bodies also suggested they had been hit with some form of explosive devices. “In some cases, the injuries seemed to be a mix of explosive and regular gunfire wounds,” he said.

Responding to the allegations that some of the bodies had been dug up with their hands tied, suggesting they were captured or held before they were killed, Dhair said he had not seen visible signs of restraint.

“Only in one case, there were discoloration and bruising on the wrists that could possibly be due to restraints,” he said. All the men were clearly in their work uniforms and their bodies had begun to decompose.

The findings are likely to increase pressure on Israel to give a full account of the incident amid accusations of a war crime. Israel has said it is still under investigation.

This week it emerged that one of the two paramedics who survived the incident, Assad al-Nsasrah – whose whereabouts had been unknown since – was being held in Israeli detention.

The medical charity Médecins Sans Frontières said on Wednesday that Gaza was becoming a “mass grave for Palestinians”.

Aid supplies including food, fuel, water and medicine have been blocked by Israel from entering Gaza since 2 March, more than two weeks before the collapse of the ceasefire between Israel and the Palestinian militant group with a return to air and ground attacks on the territory.

Israel has said it will keep blocking humanitarian aid from entering Gaza, as it vowed to force Hamas into releasing the remaining hostages from the 7 October 2023 attacks.

The Israeli defence minister, Israel Katz, said: “Israel’s policy is clear: no humanitarian aid will enter Gaza, and blocking this aid is one of the main pressure levers preventing Hamas from using it as a tool with the population.”

“No one is currently planning to allow any humanitarian aid into Gaza, and there are no preparations to enable such aid,” said Katz, who threatened to escalate the conflict with “tremendous force” if Hamas did not return the hostages.

Amnesty International is among the aid agencies that have described Israel’s blockade on all supplies going into Gaza as a crime against humanity and a violation of international humanitarian law. Israel has denied any violations.

More than 51,000 Palestinians have died in Gaza since the conflict began, including more than 1,600 since Israel resumed airstrikes and ground operations on 18 March. The Gaza health ministry does not distinguish between combatants and civilians but has said more than half of those dead were women and children.

Another 13 people were killed in airstrikes overnight, with a well-known photographer, Fatema Hassouna, among those reported dead in the northern area of the strip.

Doctors and aid groups on the ground said the humanitarian situation in Gaza was becoming graver by the day.

“The situation is the worst it has been in 18 months in terms of being deprived of your basic necessities and the resumption of hostilities and attacks against Palestinians in all of Gaza,” said Mahmoud Shalabi, a director at Medical Aid for Palestinians, a British charity.

Israel has been accused of worsening the humanitarian situation by targeting hospitals and medical personnel working in Gaza, with two hospitals struck and debilitated by airstrikes this week. Israel has claimed Hamas has used medical facilities as a cover for terrorist operations.

The resumption of aid into Gaza has become a highly inflammatory political issue in Israel. There are 58 hostages still in Gaza, who were taken captive after the Hamas attacks on southern Israel in October 2023, with 24 believed to still be alive.

Far-right figures in prime minister Benjamin Netanyahu’s government have said no aid should be restored to the civilians of Gaza until Hamas agrees to the hostages’ release.

“As long as our hostages are languishing in the tunnels, there is no reason for a single gram of food or any aid to enter Gaza,” the national security minister, Itamar Ben-Gvir, said on Wednesday.

Donald Trump has declared that Harvard University should no longer receive federal funds, calling it a “joke” that “teaches hate and stupidity”, while his administration said the pre-eminent US university could lose its ability to enrol foreign students.

Harvard made headlines on Monday by becoming the first university to stand up against a series of onerous demands from the Trump administration, setting the stage for a showdown between the federal government and one of the US’s most prestigious institutions.

The Trump administration swiftly retaliated by announcing it would freeze more than $2bn in multiyear grants and contracts with the university. On Wednesday it was also reported by CNN that the IRS was planning to take away Harvard’s tax-exempt status.

Numerous Democratic politicians and top universities across the country have rallied in support of Harvard, but the Trump administration has doubled down, threatening to strip Harvard of its tax-exempt status and insisting that the university apologize.

The Department of Homeland Security (DHS) said late on Wednesday that Harvard would lose its ability to enrol foreign students if it did not meet demands the Trump administration demands to share information on some visa holders. The department’s secretary, Kristi Noem, also announced the termination of two DHS grants to Harvard totalling more than $2.7m.

Noem said she wrote a letter to the university demanding records on what she called the “illegal and violent activities” of Harvard’s foreign student visa holders by 30 April. “And if Harvard cannot verify it is in full compliance with its reporting requirements, the university will lose the privilege of enrolling foreign students,” she said in a statement.

A spokesperson for Harvard said it was aware of Noem’s letter and that the university stood by its statement earlier in the week to “not surrender its independence or relinquish its constitutional rights”, while saying it would comply with the law.

As part of an ongoing government review of various universities over allegations of antisemitism following the student-led campus protests against the war in Gaza last year, the Trump administration sent a letter to Harvard University on Friday outlining a list of demands it must meet in order to “maintain Harvard’s financial relationship with the federal government”.

It demanded Harvard close all diversity, equity and inclusion programs; share various admission details with the government; report foreign students who commit conduct violations to federal authorities; commission an outside party to audit each academic department to make sure the student body, faculty, staff and leadership is “viewpoint diverse”; and more.

On Monday, Harvard’s president, Alan Garber, responded that the university would not yield to the government’s demands, describing them as “an attempt to control the Harvard community”.

“The University will not surrender its independence or relinquish its constitutional rights,” he said. “The administration’s prescription goes beyond the power of the federal government. It violates Harvard’s first amendment rights and exceeds the statutory limits of the government’s authority under Title VI. And it threatens our values as a private institution devoted to the pursuit, production, and dissemination of knowledge.”

He added: “No government – regardless of which party is in power – should dictate what private universities can teach, whom they can admit and hire, and which areas of study and inquiry they can pursue.”

Other universities responded quickly. In a statement on Tuesday, the acting president of Columbia University said that it would “reject any agreement in which the government dictates what we teach, research, or who we hire”.

This comes after Columbia agreed to several demands from the administration last month after the White House pulled $400m of research grants and other funding from the school over its handling of the protests against the war in Gaza.

“To put minds at ease,” Columbia’s acting president, Claire Shipman, wrote on Tuesday, “though we seek to continue constructive dialogue with the government, we would reject any agreement that would require us to relinquish our independence and autonomy as an educational institution.”

The president of Stanford University, Jonathan Levin, and the school’s provost, Jenny Martinez, also released a statement in response to Harvard’s decision, praising the university.

“Universities need to address legitimate criticisms with humility and openness,” Levin and Martinez wrote. “But the way to bring about constructive change is not by destroying the nation’s capacity for scientific research, or through the government taking command of a private institution.”

Christopher Eisgruber, the president of Princeton University, also weighed in. “Princeton stands with Harvard,” he wrote. “I encourage everyone to read President Alan Garber’s powerful letter in full.”

So did Barack Obama. “Harvard has set an example for other higher-ed institutions – rejecting an unlawful and ham-handed attempt to stifle academic freedom, while taking concrete steps to make sure all students at Harvard can benefit from an environment of intellectual inquiry, rigorous debate and mutual respect,” the former president wrote. “Let’s hope other institutions follow suit.”

Maura Healey, the governor of Massachusetts, where Harvard is located, also praised the university for “standing against the Trump Administration’s brazen attempt to bully schools and weaponize the US Department of Justice under the false pretext of civil rights”.

In response, Trump threatened Harvard’s tax-exempt status. Most universities in the US are exempt from federal income tax under the US tax code because they are considered to be “operated exclusively” for public educational purposes.

Later on Tuesday, the White House press secretary, Karoline Leavitt, told reporters that Trump “wants to see Harvard apologize”.

Then on Wednesday morning, Trump took to social media again to attack Harvard on his social media platform, Truth Social.

“Harvard is a JOKE, teaches Hate and Stupidity, and should no longer receive Federal Funds,” Trump wrote in the lengthy post. “Thank you for your attention to this matter!”

Reuters contributed to this report

Venice’s entrance fee will resume from Friday, with the main novelty this year being that last-minute day-trippers will pay double.

Last year, as part of an experiment aimed at dissuading day visitors during busy periods, Venice became the first major tourist city in the world to charge people to enter.

Although the initiative made little impact on visitor numbers, it did rake in €2.4m for the lagoon city’s coffers, much more than expected, and Venice authorities still believe it will eventually contribute to helping the Unesco world heritage city tackle overtourism.

This year’s levy, which is bookable online, remains €5, but will double if bought within three days before arrival in the city. Furthermore, it has been expanded to apply on 54 dates, mostly weekends, between 18 April and 27 July, almost double the number of days compared with last year. The measure applies between 8.30am and 4pm local time.

Visitors are provided with a QR code which they will need to present to stewards hired to patrol the city’s main entrance points, for example Venezia Santa Lucia train station.

Anyone who books an overnight stay in Venice is exempt from paying the fee, as are tourists from the wider Veneto region, which is where most day-trippers come from, as well as children under the age of 14. But even if a visitor has booked a hotel room they are still obliged to register their presence on the website.

Last year set a new record for visitors to Venice and its wider area, with more than 3.9 million staying overnight in the city’s historic centre. However, roughly 30 million people visit each year, the majority coming just for the day.

More than 35,000 day-trippers have already booked a ticket, according to the local news website Venezia Today.

Simone Venturini, Venice’s councillor for tourism, said that while there was “no magic wand” solution to a problem affecting many European tourist cities, the access fee scheme “represents a tangible and innovative tool” in terms of data analysis and managing visitor flows.

“It will be a long journey, but from now on the city will be able to rely on objective data rather than mere estimates to understand the phenomenon of overtourism,” he said. “Our goal is to encourage quality tourism – overnight stays – that respects the city and seeks to engage with it on a deeper level, embracing its unique character and rhythm.”

Another goal was to “strike a better balance between the rights of those who live in Venice and those who wish to visit it”, he added.

While the fee was mostly embraced by tourists last year, it was bitterly contested by Venice’s residents. Many of them believe the only real way to achieve more sustainable tourism would be to target the people who stay overnight by clamping down on short-term holiday lets and improving services for the year-round population, which in 2022 fell below 50,000 for the first time.

Giovanni Andrea Martini, a Venice councillor for the opposition, is among the fee’s most prominent critics.

“It has made absolutely no difference,” he said. “The numbers have actually been increasing. In recent days, we have been overwhelmed.”

Although there have been no new protests against the fee, residents have objected to attempts to encourage tourists to visit lesser-known areas of Venice’s main island.

“It is a measure aimed at reducing tourist pressure but naturally it has provoked anger among people living in these areas as it will disrupt their peace,” said Martini. “It is becoming even more tragic for those who live here.”