The low-lying clouds over the city lit up for a split second, video footage showed, then streaks of dozens of glowing warheads plummeted out of the sky.

Booms unlike anything the war-weary residents had heard before thundered through the streets of Dnipro, a central Ukrainian city with a population of about one million.

The main contours of the attack on Thursday morning soon came to light: President Vladimir V. Putin said Russia had test fired an intermediate-range missile from its arsenal designed to deliver nuclear weapons, though without the nuclear warheads aboard.

The Russian strike caused little damage, but it capped a dizzying week of tit-for-tat moves in the war in Ukraine, shifting focus from the ground assaults on the battlefield to a Cold War-style missile brinkmanship. In the previous two days, Ukraine had fired longer-range missiles provided by the U.S. and Britain at military targets inside Russia. Mr. Putin made clear that the Russian missile test was a response to those strikes — a warning to the West to reconsider military aid for Kyiv.

The long-range missile duels have been waged jointly with the fighting on the frontline, but are having little discernible influence on the ground, suggesting that they serve a political purpose rather than a military one.

Ukraine is hoping for military gains that will provide leverage in any cease-fire negotiations. Moscow is elevating threats of nuclear war before President-elect Donald J. Trump is inaugurated in January. Mr. Trump has expressed skepticism about continuing American military support for Ukraine and said he intends to broker a peace agreement in the war.

In Ukraine, the strike on Dnipro raised anxiety, but when it was over it had changed little in the war: Neither the U.S.-provided missiles Ukraine was recently granted permission to fire into Russia nor the experimental missile Russia sent back are available in sufficient enough quantities to have a significant military effect, analysts say.

But Ukraine is still at a significant disadvantage overall on the battlefield, where its outmanned forces are slowly retreating under intense Russian assaults.

Even with the new permission to strike deeper into Russia, “Ukraine is rapidly approaching a point where, if it does not address the manpower issue, then it will struggle to defend the length of the front,” the Royal United Services Institute, an analytical group affiliated with the British military, wrote of Ukraine’s prospects. Without more soldiers, the analysis said, “the collapse in fighting positions will accelerate.”

Russian assaults by Saturday had reached the outskirts of another Ukrainian stronghold, Velyka Novosilka, in the east, battlefield maps showed. And after weeks of fighting, Russian troops were close to surrounding the town of Kurakhove, threatening to encircle the Ukrainian garrison inside.

Speaking on Saturday, Ukraine’s president, Volodymyr Zelensky, said that Mr. Putin had timed Thursday’s strike ahead of the coming U.S. presidential inauguration. Russia’s goal, he said, is to expel Ukraine from a pocket of Russian territory it holds before Mr. Trump takes office. The new missiles were part of this Russian plan, he added.

“I am sure he wants to push us out by Jan. 20,” Mr. Zelensky said, speaking of Mr. Putin. “It is very important for him to demonstrate that he is in control of the situation.”

In Ukraine, the fear is Russia will seek to escalate in anticipation of talks, pursuing a strategy of placing as many threats as possible on the table before negotiating to take them away.

“Putin’s actions are not aimed at today or tomorrow, they are aimed at Jan. 20,” when Mr. Trump becomes president, Valentyn Badrak, a military analyst at the Center for Russian Studies, said on Ukrainian television. “He wants to influence Trump and bargain for more.”

Throughout the fall, North Korean soldiers began arriving in Russia and U.S. and Ukrainian officials say about 11,000 of them will join Russian forces in the southern Russian region of Kursk, where Ukraine launched an incursion in August. The aim is to expel Ukraine from the territory it seized.

Western nations said that bringing in combat troops from a third country represented an escalation by Moscow, and cited that as the justification for allowing Ukraine to use a type of American ballistic missile called an ATACM to fire into Russia. But the agreement is limited to the area in which North Koreans are deployed. The United Kingdom quickly followed suit with permissions to fire its Storm Shadow cruise missiles into Russia.

Ukraine lost little time in striking its first blows, hitting a Russian ammunition depot with American ballistic missiles on Tuesday and a command post with British cruise missiles on Wednesday.

Russia responded by formalizing a new doctrine that lowered its threshold for the use of nuclear weapons, then fired the missile in a test launch.

What exactly was launched is a matter of debate. The Pentagon described the missile as based on a decade-old Russian design called RS-26 Rubezh. Mr. Putin said it was an experimental new design called Oreshnik.

On Friday, Ukraine’s military intelligence agency, HUR, offered details of the weapon: It flew in at about 11 times the speed of sound and before impact released six warheads that broke into 36 small submunitions. Its flight time from the Astrakhan region of Russia to Dnipro was about 15 minutes.

The weapon also had one ability associated primarily with nuclear-armed missiles: the ability to release multiple, smaller warheads, the effect that lit up the early morning sky in Dnipro.

When each warhead can be aimed separately, which was not clear during Thursday’s strike, the smaller warheads are known as MIRVs, or multiple independently targetable re-entry vehicles.

Ukrainian analysts, however, have said the damage in the aftermath of the strike appeared negligible.

Ukrainian authorities are investigating whether the missile carried only dummy warheads, said Roman Kostenko, the chairman of the Defense and Intelligence Committee in Ukraine’s Parliament. If the warheads did explode, they did so with only minimal force, he said.

In an interview on Saturday, Mr. Kostenko pointed to a photograph showing a crater caused by the impact of the strike. It was about five feet across, in a sidewalk still covered in autumn leaves and with no other visible damage nearby.

The small crater, he said, suggested that an object had hit the ground with force, but had not necessarily exploded. A similar crater could be created with about two pounds of high explosive, he said. A tiny payload.

“If the missile were really fired empty, we should understand it as entirely a demonstrative” strike, with no actual military purpose, he said.

Ukraine does not have air defense systems capable of intercepting such missiles. On Friday, Mr. Zelensky said his minister of defense had requested additional systems from Western partners to counter future strikes.

The American missiles Ukraine was allowed to launch into Russia will have some impact. They have forced Russia to move planes from airfields near the border, and could help stymie Russia’s offensive in the Kursk region.

But Ukraine has too few ATACMS to significantly harm Russia’s military logistics near the border, some military analysts say. The U.S. provided Ukraine with several hundred ATACMS, and some estimates suggest there are fewer than 100 remaining.

“The United States is unable to give us the required quantity,” Col. Serhiy Hrabsky, a commentator on the war for Ukrainian media, said in an interview. For now, he said, the math doesn’t add up for these missiles to make a difference in the war.

After the Russian missile launch on Thursday, a deputy Pentagon press secretary, Sabrina Singh, said the United States would continue arming Ukraine. American officials, she said, “take seriously rhetoric coming out of Russia, but our focus remains on Ukraine and supporting Ukraine.”

And Ukraine has no choice but to continue fighting, despite the latest threat of nuclear war implied by the Russian missile launch, Mr. Kostenko, the defense chairman, said. Ukraine will not alter how it is fighting the war, he added, including striking back at targets in Russia in self-defense.

“Ukraine should continue doing what it is doing,” he said. “You cannot fight the war in another way.”

Nataliia Novosolova contributed reporting from Kyiv, Ukraine.

An Israeli airstrike on a residential building in central Beirut killed at least 20 people on Saturday, the Lebanese Health Ministry said, part of an intensifying Israeli military campaign that appears aimed at pressuring Hezbollah into a cease-fire deal.

The strike was an attempt to assassinate a top Hezbollah military commander, Mohammad Haidar, according to three Israeli defense officials who requested anonymity to discuss sensitive military operations. Hezbollah officials on Saturday afternoon said that none of the group’s leaders were at the site of the airstrike, and later in the day, one of the Israeli officials said Mr. Haidar was not killed.

Over the past week, Israeli ground troops made a concerted push deeper into southern Lebanon while Israel intensified its bombardment of the Dahiya, a cluster of neighborhoods on the southern outskirts of Beirut that are effectively governed by Hezbollah.

The death toll in the latest strike was expected to rise, and at least 66 people were injured, according to the Health Ministry. The strike came just after 4 a.m., jolting Beirut residents awake with thundering explosions that left much of the city enveloped in acrid smoke. It was the third strike this week in central Beirut, an area that had largely been spared since the war between Hezbollah and Israel escalated.

Lebanon’s health minister, Firass Abiad, said the airstrike hit a multistory building that was believed to house at least 35 people in the Basta neighborhood of Beirut, an area that is home to both Sunni and Shiite Muslims and close to several Western embassies. Hezbollah is a Shiite militant group and Shiite communities in southern and eastern Lebanon have borne the brunt of Israeli attacks over the past few months.

The war in Lebanon has killed more than 3,500 people and forced almost a quarter of the population to flee their homes. Some Shiites who fled the Dahiya have taken refuge in Basta, according to residents of the area.

“There was no prior warning,” Mr. Abiad said of the Basta strike in a phone interview. “It appears there are still bodies under the rubble.”

A crowd of onlookers and rescue workers gathered outside the blast site. Among them were Iman Ismael, a refugee from Syria, and her 10-year-old son, who were waiting for news about four relatives who had lived in the destroyed building.

“They are still missing,” she said. “God, please let them survive.”

The building was just three doors down from another building that Israel bombed last month in an attempt to kill another senior Hezbollah official. Zainab Rummu, 54, said the strike in October had felt like “the end of the world” and forced residents to repair their damaged homes and neighborhood. Now they would have to do it again.

“We thought it was over. No more danger,” she said. “Now where can I go?”

Later on Saturday morning, Israel issued new evacuation warnings for the Dahiya.

The new wave of attacks on Lebanon came as Israel and Hezbollah appeared to be inching toward a cease-fire deal.

An Israeli official said Friday that there was “cautious optimism” about prospects for a truce in negotiations mediated by the United States, though Lebanese officials were less sanguine about a deal. Both Israel and Hezbollah have said they will keep fighting as negotiations go on.

Heavy fighting was reported overnight in the southern Lebanese town of Khiam which the Israeli military has been attempting to encircle in recent days, according to Lebanon’s state-run news agency. Hezbollah said on Friday that it had repeatedly attacked Israeli forces in and around the large town, which lies around three miles from the Israeli border.

Israel began an intensified military campaign against Hezbollah in September in response to almost a year of near-daily rocket attacks on northern Israel. Hezbollah said the attacks were in solidarity with its ally, Hamas, in Gaza. Both armed groups are back by Iran.

Israel said it was going to war in Lebanon to stop the rockets and to allow tens of thousands of displaced Israelis to return to their homes in northern towns that were evacuated last year. But the rocket attacks have not ceased, and those residents have been unable to return home.

The war has become the bloodiest conflict inside Lebanon since the country’s 15-year civil war, which ended in 1990.

Euan Ward, Ben Hubbard and Hwaida Saad contributed reporting.

The day after President Vladimir V. Putin of Russia raised the stakes in tensions with the West, many Russians awoke on Friday feeling anxious that the prospect of nuclear war had come slightly closer.

But in Russia’s tightly controlled news media and pro-government social media channels, there were only fawning reactions to the Russian leader’s new round of saber-rattling and promises that Moscow’s enemies would “tremble in fear.”

Mr. Putin announced late Thursday that Russia had launched a new intermediate-range ballistic missile at Ukraine, in response to Kyiv’s first use of U.S. and British missiles against targets inside Russia this week. Russia, he said, also has the right to strike nations “that allow their weapons to be used against our facilities.”

In the West, Thursday’s launch of the nuclear-capable Oreshnik missile and Mr. Putin’s remarks were perceived as a threat against Ukraine and its allies, and drew widespread condemnation as an escalation. In Russia, the events were billed as an important sign that the Kremlin would enforce its red lines, with the implication that enforcement could include nuclear weapons.

“This topic used to be a taboo in Russia,” said Denis Volkov, the director of the Levada Center, one of the few independent pollsters in Russia. “Within the elites, the consensus is shifting toward talking about it much more openly, and that Russia should make the West understand that it is serious.”

Russians have been largely desensitized to the Kremlin’s frequent bellicose statements and claims of being besieged by the West since Russia invaded Ukraine in February 2022. But there are also signs that more Russians have come to accept and even cheer on Mr. Putin’s hawkish stance, accompanied by a steady stream of government and media claims that Ukraine and the West are the aggressors.

A growing number of Russians favor the initiation of peace talks, too, but the number of people who accept the use of nuclear weapons has risen slightly, polls suggest.

Though almost half the Russians surveyed in a poll this year found the use of nuclear weapons “unacceptable,” there has been a slight increase since last year in the number who consider it acceptable, to 34 percent, Mr. Volkov said. He did not discount that after Mr. Putin’s latest speech and the breathless media coverage that followed, that number could rise further.

Support for nuclear force dovetails with support for the Kremlin, Mr. Volkov said. But for many opposition-minded Russians, the use of a nuclear-capable missile still came as a shock.

“Sometimes it feels like I no longer care. You get so apathetic, but the ongoing background noise is one thing and using an ICBM for the first time is something else,” said Olga, 50, a university professor from Moscow, referring to early reports that misidentified the missile as intercontinental.

Olga, who asked that her surname be withheld for fear of repercussions, is strongly antiwar. She said she felt “a little anxious,” though she believes Mr. Putin is bluffing when he threatens to strike targets in the West.

Mr. Putin’s address did not trigger any visible displays of public anxiety in Russia, but the ruble, already battered by a new package of U.S. sanctions on Thursday, dropped further on Friday. The Russian currency on Friday afternoon was trading at its lowest point against the dollar since March 2022.

The threat of expanding the conflict beyond Russia and Ukraine and possibly using nuclear weapons seemed to fall on fertile ground: the apathy and helplessness that have gripped many Russians since the invasion began.

Ksenia A. Sobchak, a prominent media personality whose father was Mr. Putin’s boss in the 1990s, summed up the sentiment on Telegram with gallows humor: “He didn’t say if they will use nukes or not. But do they have to do it right now? Can they at least wait until after the holidays?”

A flagship news show on a state-owned TV channel, Rossiya-1, on Friday morning covered Mr. Putin’s big reveal with gusto, demonstrating the Oreshnik missile’s abilities in a set of sleek graphics. In one, a missile launcher placed on a map of Europe sent projectiles from western Russia to western Europe, reaching “all European capitals.” The host, Olga V. Skabeyeva, boasted, “Even London!”

Ms. Skabeyeva sought to portray Mr. Putin as magnanimous when she noted that Russia was under no obligation to notify the United States ahead of Thursday’s launch, but did so anyway: “We sent a notice to the Americans so that we avoid a Third World War.”

Russian state media, which have always been sensitive about Western press coverage of Russia, also portrayed Mr. Putin’s remarks as a public relations victory. On Friday, a lot of programming was devoted to a detailed press digest, citing news reports from the United States to Saudi Arabia and boasting that the president won front pages around the world.

Rossiya-1 on Friday broadcast a report on social media metrics, bragging that “Oreshnik” trended globally. The state-owned RIA Novosti news agency even published an article based on social media replies to a post by Dmitry A. Medvedev, a former Russian president who gloated over the missile strike. The report suggested that “residents of the West were rushing to offer their apologies” to the Kremlin for Ukrainian strikes on Russian territory.

While Russian media insisted that Mr. Putin was merely responding to Western aggression, some Kremlin-linked figures made it clear that his speech intended to scare the West into withdrawing support from Ukraine.

“Let them tremble in fear,” Andrei V. Kartapolov, who heads the defense committee in the State Duma, the lower parliamentary house, told the Russian news agency Tass on Friday. “We’re fighting for the right cause.”

In popular social media groups typically focused on local news, Russians weighed in on Mr. Putin’s speech, with some condemning his apparent appetite for escalation and others cheering on Russia’s army.

In the southern city of Rostov-on-Don, one resident on a popular Telegram group said Russia “has been set 25 years back in its development — what for?”

In Kursk, which became a frontline city this summer after the Ukrainian army seized swaths of Russian land near the border, some Russians on a popular group on VKontakte, a social network, celebrated the missile attack against Ukraine. Others wondered sarcastically if Mr. Putin would call an evacuation were he to strike nearby — many locals have criticized the government for not evacuating parts of the region as evidence mounted that a Ukrainian attack was imminent.

Meanwhile, Russian supporters of the war rushed to praise the president for upping the stakes in the confrontation with the West. Pro-Kremlin bloggers have been sharing memes showing Mr. Putin as an action hero in a movie poster, alluding to wordplay between “Oreshnik,” the name of the Russian missile, and the word “oreshek,” meaning “nut,” which is used in the Russian title of the American blockbuster “Die Hard.”

“Oreshnik. Premiere in Dnipro, November 21, 2024,” said a mock movie poster shared on a popular pro-war Telegram channel.

Voenkor Kotenok, a popular blogger, praised the attack on Dnipro as “a kind of a rain of fire from the sky that was like a movie for the Ukrainians.” But like some other pro-war commenters, he lamented that the Kremlin had notified the United States shortly before the missile launch.

Russia is “too humane and merciful,” he said. “An enemy is to be killed, not warned.”

The six young children had just shared snacks bought from a corner store when they began convulsing. The children, all of them under 8, died moments later, adding more victims to a wave of food poisoning that the authorities say has killed nearly two dozen children in a few months.

The South African government declared the poisonings a national disaster on Thursday, taking action after President Cyril Ramaphosa laid out the scale of the danger. At least 890 people have fallen sick, many of them children, he said in a televised address last week, adding that the cause was believed to be a pesticide used by business owners and vendors to fight a rat infestation in neglected townships. Expired and counterfeit food products have also been blamed by grieving family members and some residents.

The size of the outbreak, with deaths reported in provinces across the country, has forced South Africa’s leaders to reckon with the everyday consequences of dysfunctional government departments that are tasked with overseeing food safety, waste disposal, and small business regulations.

The government declared the emergency in a news conference held by half a dozen cabinet ministers, representing portfolios from health and education to agriculture and trade. Officials have also fanned out to inspect stores and to visit mourning families in townships where angry residents have turned on shop owners, many of whom are immigrants.

“These products are just as likely to be sold in shops owned by South Africans,” Mr. Ramaphosa said during his address, trying to curb the anger in a country where violence has in the past flared up between South Africans and migrants from other African countries and South Asia.

After the deaths of the six children in Johannesburg last month, South Africa’s National Institute for Communicable Diseases found traces of terbufos, a hazardous pesticide used in agriculture, in the contents and on the packaging of a snack found with one of the children, Mr. Ramaphosa said. Terbufos, a colorless or pale yellow liquid used on crops, can be fatal if ingested or inhaled, or if it comes in contact with humans, according to the National Institutes of Health.

In other cases, South African health authorities found evidence of aldicarb, an agricultural pesticide that is highly toxic to humans. The pesticide has been banned in South Africa since 2016, Mr. Ramaphosa said.

These highly toxic chemicals had been adopted as a “street pesticide,” he said, to fight a growing rat infestation in South Africa’s formerly segregated townships and mushrooming shanty towns. In poor communities, where municipalities fail to regularly collect waste, business owners had turned to the toxins to keep vermin away.

In yet other cases, expired food products have been blamed as the cause of death. Some residents and outraged families of children who died have, stoked by longstanding anti-immigrant sentiments, blamed foreign owners of corner stores for the poisonings. The owners, they claim, use pesticide to kill rats and sell expired food items or counterfeit brands of processed food to poor communities where people cannot afford to shop in supermarkets.

The stores, known as spaza shops, are often built in a backyard and operated by migrants. In response, the government will now register these shops, Mr. Ramaphosa said. The measures are likely to offer little comfort to the families around the country who have buried young children. In Kimberley, a city in South Africa’s Northern Cape Province, a 4-year-old girl died after eating bread last month. In another province, the Eastern Cape, a 9-year-old girl died after reportedly eating a packet of crisps.

In Johannesburg this week, a 5-year-old boy reportedly died just 20 minutes after eating a snack. His home, in the city’s Soweto township, was not far from where the six friends died just weeks earlier.

“Because these children are friends, they share everything,” Triphina Msimango, who lost her grandson, told the South African Broadcasting Corporation last month. “They shared the snacks among themselves, not knowing they were eating poison.”

After a few days without food, the hunger stops. The body, while weak, “learns how to just function.” That is how Laila Soueif, an Egyptian mathematician and professor, describes her hunger strike, which reached 55 days on Saturday.

She stopped eating on Sept. 29, when it became clear that her son, Alaa Abd El Fattah, one of Egypt’s best known political prisoners, would not be released after serving a five-year sentence.

Egyptian authorities had sent him a written notice that they would not be counting his two years of pretrial detention, an increasingly routine practice in the country. Mr. Abd El Fattah, 43, is now scheduled for release in 2027, although he and his family fear he may be held indefinitely.

His plight is just one example of the crushing campaign against dissent orchestrated by Egypt’s president, Abdel Fattah el-Sisi, since he came to power in a 2013 military takeover, with tens of thousands of political prisoners now incarcerated, according to rights groups.

Ms. Soueif, 68, said she plans to continue her hunger strike — surviving on water, rehydration salts and sugarless tea and coffee — until he is free.

“I won’t back down and I will be very visible,” Ms. Soueif said in an interview in London on Thursday. “When people ask, ‘What do you think you’re doing?’ I say, ‘I’m creating a crisis.’”

She had flown to London from Cairo ahead of a Nov. 27 meeting with David Lammy, Britain’s foreign secretary, who she hopes will lean on the Egyptian government to help secure the release of her son, a British and Egyptian dual citizen. But such diplomatic efforts have a mixed rate of success in the past.

Mr. Abd El Fattah came to prominence as one of the most eloquent voices of Egypt’s 2011 Arab Spring uprising, which toppled its longtime, authoritarian ruler, Hosni Mubarak. But things did not go the way that liberal revolutionaries had hoped. An Islamist political party took power in Egypt’s first democratic presidential election, and widespread backlash to its rule allowed Mr. el-Sisi to seize power.

Mr. Abdel Fattah chronicled that period, and the authoritarian clampdown that followed, in social media posts, newspaper columns and essays published in 2021 as a collection, “You Have Not Yet Been Defeated.”

Much of the time, he was writing from prison. First arrested in 2006 for protesting in favor of judicial independence, then in 2011 for an article critical of Egypt’s military, he was detained again from 2013 until March 2019 on charges of organizing an illegal protest. In September that year he was arrested again and sentenced in 2021 to five years for sharing a Facebook post about prison abuses.

While incarcerated, he applied for British citizenship through his mother, who is a dual national. Since then, his family has called on the British government to use its diplomatic and economic ties with Egypt to secure his release.

Mr. Lammy had campaigned for Mr. Abd El Fattah’s release while his party was in opposition, meeting with the family, joining them in a protest outside the Foreign Office and raising the issue of his detention in Parliament. So when Mr. Lammy became foreign secretary in July under a new Labour government, the family hoped he would use his new status to pressure Egypt.

They pointed to Britain’s success in negotiating the 2022 release of Nazanin Zaghari-Ratcliffe, a British-Iranian citizen who had been detained by Tehran for six years, though in that case London had the added bargaining chip of a longstanding payment owed to Iran over a failed arms deal.

So far, there has been no progress in her son’s case, Ms. Soueif said. Egyptian authorities did not respond to requests for comment. A spokesperson for Britain’s foreign office said in a statement that Mr. Lammy had raised the case with Egypt’s foreign minister “on a number of occasions, most recently on Nov. 14,” adding: “Our priority remains securing consular access to Mr. El-Fattah and his release so he can be reunited with his family.”

In November 2022, Mr. Abd El Fattah, who had already been on hunger strike for months, stopped drinking water as Egypt hosted the United Nations COP 27 climate conference.

During that event, activists called on Egypt to “free Alaa,” and world leaders pushed for his release in meetings with Mr. el-Sisi. But Egypt did not cave. About a week later, Mr. Abd El Fattah resumed eating and drinking after suffering an emotional and physical breakdown.

Western pressure has helped free some other Egyptian political prisoners in recent years, and the authorities have occasionally released prominent detainees in what analysts and opposition politicians say is partly an attempt to clean up Egypt’s international image. (The limited releases were dwarfed by new arrests, rights groups say.)

But diplomats in Cairo say that raising specific cases with Egyptian officials can backfire.

“We have this everlasting dilemma: The Egyptian authorities don’t like to be pressured — don’t like to be pushed,” Ms. Soueif said. “But my position is that they won’t do anything if they’re not pressured and not pushed.”

Ms. Soueif has challenged the idea, which has circulated among some of her son’s supporters, that Mr. el-Sisi is personally opposed to his release. She noted that Mr. el-Sisi had grievances with two other well-known prisoners, who were nevertheless released last year.

That gives her hope that Mr. Abd El Fattah can yet be freed, asserting: “It is doable.”

British diplomats in Cairo have consistently pressed for consular visits and for his release since he gained British citizenship, but with no success. These days, it is even less clear what leverage Britain can exert over Cairo. Egypt is in a stronger position internationally than in 2022.

The war in Gaza, which borders Egypt, has led Western backers such as the United States, the European Union and the International Monetary Fund to flood Egypt with aid, seeing Egypt as an indispensable partner in a crisis-wracked region.

This is not Ms. Soueif’s first hunger strike. A decade ago, she and her daughter, Mona, did not eat for 70 days. That was to protest a previous imprisonment of Mr. Abd El Fattah and of Sanaa, her youngest daughter, both of whom were jailed for taking part in separate street protests.

She said she would consider progress on her son’s case as a reason to end her current strike, but she is prepared for the worst.

“If — for this crisis to hit home — it needs me to go as far as falling apart or dying, then that’s what will happen,” she said. “I hope I don’t get there.”

Violent clashes erupted overnight between Sunni and Shiite tribes in northwestern Pakistan, leaving at least 25 people dead and markets, homes and government properties in flames, officials and residents said on Saturday.

The violence occurred in Kurram, a scenic mountainous district in Khyber Pakhtunkhwa Province, which borders Afghanistan. It took place in the same area where gunmen ambushed convoys of vehicles on Thursday, killing 42 people, all Shia, despite the protection of security forces.

Pakistan is overwhelmingly Sunni Muslim, but Kurram’s population of 800,000 is nearly half Shiite Muslim, a dynamic that contributes to tribal and sectarian tensions. Officials and residents said that the violence started on Friday afternoon in parts of the district where Sunni and Shiite groups live close to each other.

Muhammad Shoaib, a resident of a Sunni-populated town where the Shiite convoys came under attack on Thursday, said that hundreds of heavily armed people from the rival sect had attacked the main market on Friday night and set fire to dozens of shops and houses.

“For hours on that night, heavy gunfire was exchanged between both sides, with large weapons being used freely,” said Mr. Shoaib, who on Friday morning had moved his family to stay with relatives in a neighboring district out of fear for their safety.

“We knew that there would be a retaliatory attack,” he said. “It’s a cycle of violence that we have been witnessing and suffering for years now.”

The authorities were still working to restore order and prevent further bloodshed.

Javed ullah Mehsud, a senior district administration official, said that at least 25 people had been killed in the violence. He said clashes were continuing in at least three locations.

“Efforts to restore peace are underway through the deployment of security forces and engagement with local tribal councils,” Mr. Mehsud said. A curfew has been imposed on the main road, and the markets remain closed, with all traffic suspended.

Friday at midday, the victims of Thursday’s deadly attacks were laid to rest as thousands of mourners gathered to pay their respects.

“It is not new for us to bury such a large number of people in one day,” said Mukhtar Hussain, a mourner from Parachinar, a Shia-majority town in Kurram where most of the victims were from. “As Shiites, we are being killed everywhere — in markets, mosques, on roads — everywhere,” he said.

Shiite groups in Pakistan have announced a three-day mourning period for Thursday’s killings and have organized protests in all of Pakistan’s major cities.

Allama Ahmed Iqbal Rizvi, a Shiite leader, said that various militant groups, such as Tehreek-e-Taliban Pakistan and the local affiliate Islamic State affiliate — called Islamic State Khorasan Province, or ISIS-K — had been targeting the Shiite population in Kurram for a long time.

“It is the incompetence of the government and state institutions,” said Mr. Rizvi, addressing a protest after Friday prayers in the port city of Karachi. He complained that they could not protect citizens traveling on the 155-mile road that links Kurram with Peshawar, the provincial capital.

That road, which is where the convoys came under attack, is a lifeline for the district. It had reopened only recently after being closed for three weeks following an ambush on Oct. 12 that left at least 16 dead.

During the closure, Parachinar residents were cut off from essential supplies like food and fuel.

This month, thousands of people from Parachinar staged a peaceful 10-mile march to demand the road’s reopening and security guarantees. The authorities responded by temporarily restoring access and promising government-protected convoys three times a week.

It has been a particularly deadly year in Kurram. In late July, a weeklong clash between Sunni and Shiite communities left 46 dead and hundreds injured. Another bout of violence in September claimed 45 lives and wounded dozens.

Experts attribute the escalation in sectarian conflicts to a complex interplay of factors rooted in the area’s socio-economic and historical context.

Among them are “close proximity to Afghanistan, a significant Shiite population, tensions over land ownership and decades of weak governance under colonial tribal laws,” said Tahmeed Jan, an Islamabad-based researcher who has worked in the area.

“Socio-economic disparities, with Shiite-majority areas often better developed than Sunni-majority regions, which struggle with inadequate infrastructure and lower literacy rates, further exacerbate these tensions,” Mr. Jan said.

He promised salvation for a country “in ruins” — an end to immigration, a civil service stripped of entrenched left-wing opponents, a judiciary purged of meddlesome judges and a news media giving voice to the people instead of elites.

Those campaign pledges — similar to ones made by Donald J. Trump during his successful bid for a second term as U.S. president — helped bring Jaroslaw Kaczynski and his nationalist Law and Justice party to power in Poland in 2015.

More than a year after an election that ended that party’s eight-year rule, its liberal successors are still struggling to undo the “new state apparatus” that Mr. Kaczynski helped put in place and that legal experts say seriously damaged Poland’s legal system.

Unwinding the legacy of populist conservative rule “takes longer than you expect,” said Adam Bodnar, the justice minister at the forefront of the new government’s efforts to reverse Poland’s retreat from liberal democracy under Law and Justice.

That retreat involved the politicization of Poland’s judiciary, a near total ban on abortion, the hijacking of public broadcasting for propaganda and a deep rift with the European Union.

Mr. Bodnar, speaking before the U.S. election, pointed to Prime Minister Viktor Orban of Hungary as an example of the tenacity of right-wing populist rule. Future successors to Mr. Orban, in power since 2010 and an ally of Mr. Trump, Mr. Bodnar said, will face formidable obstacles. “I would be very afraid,” he added.

Mr. Kaczynski and Law and Justice are also fans of Mr. Trump, and the party’s legislators chanted his name in Parliament after he was elected again. The current government, led by Prime Minister Donald Tusk, who made no secret of his preference for Vice President Kamala Harris, offered the American president-elect polite congratulations.

Mr. Bodnar said he was picking his way cautiously through a legal minefield left by the previous government. Many hazards have yet to be defused but, he added, “We now know exactly where all the mines are.”

When he took office, Mr. Bodnar brought back European Union flags to the Justice Ministry that his hard-line predecessor had banished.

But other changes, particularly the rebuilding of a court system that legal experts say was undermined by the previous government’s political agenda, have lagged, as have efforts by Poland’s coalition government to deliver on election promises to reverse the criminalization of nearly all abortions.

On the issue of immigration, the current government has dropped the inflammatory language of Mr. Kaczynski, who denounced migrants during the 2015 election campaign as carrying “parasites and protozoa.” But it has continued and even strengthened his hard-line stance, with Mr. Tusk announcing that Poland would suspend recognizing asylum requests.

Mr. Bodnar said the biggest obstacle to undoing what he sees as the damage done by Mr. Kaczynski’s party is Poland’s president, Andrzej Duda. Mr. Duda, elected separately, is a supporter of Law and Justice and has veto power over all legislation reversing changes made by Law and Justice when it was in power.

Those changes included the stacking of the Constitutional Tribunal and Supreme Court with right-wing loyalists, critics say.

“We know that with this president it will not be possible to make significant changes concerning the judiciary,” Mr. Bodnar said, and the only solution was “to wait for a new president” after elections in May.

Parliament is now controlled by a coalition of liberals, traditional conservatives and leftists. When it passed legislation in October to overhaul the constitutional court, Mr. Duda referred it for review — to the tribunal that was being targeted.

And when Mr. Bodnar, who is also prosecutor general, tried to replace the second-most senior official in the prosecutorial system, a holdover from the previous government, the president objected and the same court declared the move unconstitutional.

The setbacks highlighted the hurdles the center-right government has faced in trying to establish its electoral program in face of resistance from judges, prosecutors, state media executives and others appointed by Law and Justice.

Law and Justice left “the whole system wrapped in political ivy that is very, very difficult to remove,” said Jaroslaw Kuisz, the author of a book on the party’s push to take Poland in the same direction as Hungary under Mr. Orban.

“What is happening now is not just a normal change of government,” Mr. Kuisz added, but a “post-populist moment that can only be compared with the post-communist moment” after 1989. That was when Poland’s new democratic government had to rebuild institutions and the rule of law after decades of Communist Party rule.

While Polish Communists mostly adapted to the democratic order, Law and Justice and its appointees are fighting back, Mr. Kuisz said. “They don’t consider themselves defeated.” Mr. Trump’s election, he added, “will boost their energy to resist because they believe they are the avant-garde of history.”

Leading the resistance is Mr. Kaczynski, Law and Justice’s chairman.

“Today, unfortunately, we have to fight for a free Poland again,” Mr. Kaczynski said on Nov. 11 during an Independence Day speech, accusing Mr. Tusk of presiding over “the destruction of the country.”

After Law and Justice lost its parliamentary majority last October, Mr. Kaczynski joined a sit-in at a state broadcaster, TVP, in support of executives and journalists who, facing dismissal from jobs they owed to the previous government, had barricaded themselves into their offices and studios.

They claimed to be defending freedom of speech, an argument that largely fell flat given that the state broadcasting system had been turned into a bullhorn for right-wing propaganda.

Also fighting back hard has been the president of the Constitutional Tribunal, Julia Przylebska, an old friend of Mr. Kaczynski’s. She became president of the 15-member court in 2016 after Law and Justice appointed five new justices in violation of normal procedure. That set off street protests and led the European Court of Justice to rule that the tribunal had not been “established by law.”

The tribunal played a central role in cementing Law and Justice’s agenda, issuing rulings against abortion and the primacy of European Union law.

When Parliament passed resolutions this year demanding that Ms. Przylebska move on, along with other justices whose appointments were tainted by irregularities, she responded by vowing to hang on in a combative video posted on the tribunal’s website. Adding to a morass of uncertainty is a dispute over when her term as tribunal president ends. The government says it ended in 2022.

When the government in March stopped publishing her tribunal’s rulings in the official Legal Gazette, which meant they had no legal force, Ms. Przylebska started publishing them herself on her court’s website, saying that made them valid.

Mr. Bodnar has faced criticism both for moving too quickly and too slowly. The head of the Supreme Court, another tribunal hijacked by Law and Justice, has accused him of “Stalinist methods.” And some supporters of the new government accuse him of being too timid in removing improperly appointed judges.

“We need to cut off all the heads of this dragon at once,” Professor Krystian Markiewicz, the president of Iustitia, an association of judges, said recently.

Of Poland’s 9,000 or so judges, around a third got their positions under a nomination process introduced by Law and Justice that gave politicians a big say.

Only about 100 of the judges selected through Law and Justice’s system have so far been replaced. Parliament passed legislation in April to remove politicians from the selection process, but Mr. Duda, the president, sent the law to the Constitutional Tribunal for review.

“We must be patient, but at the same time determined to make things happen,” Mr. Bodnar said.

Other ministers chose a more radical path. When Mr. Duda blocked efforts to overhaul the state broadcasting system, the culture minister responded by dissolving the legal entities under which state television and radio stations operated.

The maneuver, which skirted and, some believe, violated the law, worked, but it prompted howls of protest from Law and Justice.

The government, Mr. Bodnar said, has been “trapped by different — either institutional or personal — obstacles to bringing the system back to order.”

He said he was making progress but added: “If you have a system that was continuously destroyed day by day for eight years, you cannot rebuild it within one year.”