In September last year, the top United Nations envoy for the Middle East peace process left a meeting with Hamas leaders in Gaza thinking that he had helped avert a major escalation.

The veteran Norwegian diplomat, Tor Wennesland, said he believed that Hamas had agreed to reduce recent tensions along the Israel-Gaza border in exchange for more work permits for Gazan workers.

But Hamas had bluffed Mr. Wennesland, along with the Israeli leadership and much of the international community. Days later, the group’s fighters attacked Israel, setting off the deadliest year in the history of the Israeli-Palestinian conflict.

It was a misconception that Mr. Wennesland now says is emblematic of the problem with the international community’s recent approach to the Israeli-Palestinian conflict.

As he retires after a four-year tenure, Mr. Wennesland, 72, says world leaders have wrongly focused on short-term fixes, including small-scale humanitarian initiatives in Gaza, at the expense of a more ambitious push for a Palestinian state.

“The feeling that Hamas had no interest in the conflict — that was the mantra, and it was wrong,” Mr. Wennesland said in a parting interview before leaving Jerusalem last weekend. “I’m somehow blaming myself for not getting that, not that I was the only one,” he added.

In the half-decade before the war, he said, the international community had focused on improving the economy in Gaza, hoping that higher levels of employment and a better quality of life in the blockaded territory might prevent more flare-ups between Hamas and Israel. Foreign leaders also focused on diplomatic deals between Israel and other Arab states, believing that they might eventually and indirectly lead to peace with the Palestinians.

Both approaches, Mr. Wennesland said, ultimately failed to solve the main issue driving the conflict in Israel, Gaza and the West Bank: the lack of a permanent settlement between Israelis and Palestinians.

“Politics failed. Diplomacy failed. The international community failed. And the parties failed,” said Mr. Wennesland, who has been involved in Mideast peace initiatives for more than three decades.

“What we have seen is the failure of dealing with the real conflict, the failure of politics and diplomacy,” he added.

The failure to reach a permanent resolution was, in some ways, caused by a rift between Hamas and its West Bank-based rival, Fatah, preventing Palestinians from forming a united front, he said. This also reflected the growing strength in Israel of right-wing leaders who oppose Palestinian sovereignty, he said.

But it was also linked to how Western leaders — distracted by the migration crisis in Europe, the coronavirus pandemic and, finally, the war in Ukraine — had stopped convincing Israelis of the need for a two-state solution and Palestinians of the need for a united front, Mr. Wennesland said.

“Politics is what ends war, and diplomacy is what ends war,” Mr. Wennesland said. But for more than half a decade, international attention has been shifting “towards dealing with the day-to-day humanitarian situation, and with less attention on the politics,” he said.

Mr. Wennesland’s stance makes him something of an outlier among Western diplomats. In private, many officials express growing doubts about the viability of a two-state solution to the conflict, particularly with the Israeli public increasingly opposed to Palestinian sovereignty. But that approach risks becoming a self-fulfilling prophesy, Mr. Wennesland said, because it allows opponents of Palestinian sovereignty to set the terms of debate.

“The spoilers have been more effective, determined and fast moving than diplomats and politicians” in the West, he said.

In many senses, the contours of Mr. Wennesland’s career reflect what he sees as the gradual shift in international focus.

In the 1990s, he worked for the Norwegian government as it helped facilitate interim peace agreements known as the Oslo accords.

A decade later, he was the Norwegian envoy to the Palestinians, amid a renewed U.S.-led push for a Palestinian state.

But by the time he was appointed United Nations special coordinator for the Middle East peace process in late 2020, the primary American focus was on peace agreements between Israel and other Arab states, including the United Arab Emirates, instead of between Israel and the Palestinians.

Now, Mr. Wennesland said, world leaders are failing to lead the discussion about what a postwar Gaza looks like.

Without significant Western resistance, Israeli officials are pushing to maintain Gaza’s isolation from the West Bank after the war. Israel considers the Palestinian Authority, which administers Palestinian cities in the West Bank, too incompetent and corrupt to take over Gaza.

But sidelining the authority would sustain the disconnection between the two territories that began in 2007, when Hamas forced the authority’s leaders from power in Gaza.

Mr. Wennesland said that it would be a mistake to cede the narrative battle to Israel, because sidelining the authority would make it harder to create a Palestinian state in both territories.

“We need to set the parameters clearly,” he said. “If Gaza is de-linked institutionally as it has been since 2007, I think it will be very difficult to reconnect.”

Hospitals have been ripped apart by airstrikes. Nearly 50,000 people have fled their homes, and tens of thousands lack running water. Civilians are being laid out in body bags on hospital floors after shells struck their neighborhoods.

Scenes from the bloodiest days of Syria’s civil war, which had lain largely dormant for several years, are now repeating themselves in the country’s northwest as pro-government forces try to beat back a surprise rebel offensive, according to aid workers, a war monitor and the United Nations, who warned of a rapidly worsening humanitarian situation.

Conditions were already dire for civilians in the area: Years of war and a powerful February 2023 earthquake had led to crushing poverty, displacement and breakdowns in services. But over the last several days, the region’s misery deepened as Russian and Syrian fighter jets have repeatedly struck Idlib and Aleppo in northwestern Syria and rebels fought to capture more territory.

The United Nations said more than 50 airstrikes had hit Idlib Province in northwestern Syria on Sunday and Monday. Four health facilities, four schools and two camps housing people displaced from earlier phases of the conflict suffered damage, it said.

Stéphane Dujarric, a U.N. spokesman, said in a briefing Monday night that a strike on a water station had also cut off access for at least 40,000 people. And the Norwegian Refugee Council, which provides aid in the region, said its humanitarian workers were reporting that bakeries and shops had shut down in Aleppo, leading to food shortages.

Mr. Dujarric said that 24 health care centers in Idlib and western Aleppo province had suspended operations amid the fighting, adding that humanitarian activities had been largely paused out of concern for aid workers’ safety.

In the city of Idlib, which the rebels fully control, several hospitals showed damage on Tuesday from what staff said were pro-government airstrikes a day earlier. At SAMS Maternity Hospital and Ibn Sina Children’s Hospital, heavily damaged incubator units for premature infants were seen.

Dr. Mohammed Hussam Kaddouh, the director of Idlib University Hospital, said on Tuesday that his facility was one of two that was knocked completely out of service by strikes.

“The strikes directly targeted the hospital,” Dr. Kaddouh said. “Right now we’re mainly relying on the remaining medical centers outside of Idlib.”

One strike hit the hospital’s eastern wing in front of the emergency room’s entrance, Dr. Kaddouh said, and another its northern wing. On Tuesday, large shards of glass were still visible in front of a reception desk. Units that housed patients were torn apart, their ceilings displaying gaping holes, with debris strewed through hallways and patient rooms.

One missile slammed through two reinforced concrete roofs and landed in the hospital’s basement, according to Dr. Kaddouh, who said no one was injured in the strikes because people inside were able to evacuate in time.

University Hospital typically serves about 1,100 patients a day and nearly 30,000 a month, Dr. Kaddouh added. Its cardiology and obstetrics and gynecology departments are the only ones in the city, he said; now patients must leave the city to find those services.

At least 44 civilians have been killed in fighting in Idlib and northern Aleppo between the start of the offensive last week and Sunday, according to the United Nations, which said the numbers were verified by local health authorities. At least 162 more were reported injured, nearly two-thirds of them women and children, it said.

The Syrian Observatory for Human Rights, a Britain-based war monitor, said at least 26 more people were killed in pro-government airstrikes across the region on Monday. On Tuesday, it reported that 20 civilians in the western city of Hama were killed when rebel factions shelled government-held neighborhoods as they tried to capture the city, and another two civilians were killed in airstrikes on the city of Khan Sheikhoun.

About 5.1 million people live in northwestern Syria, according to U.N. figures, including 3.5 million who were displaced to Idlib from other parts of the country and two million who have been living in camps or other temporary shelters. Thousands fled the recent war in Lebanon for northwestern Syria, adding to the pressure on a region where many already struggled to get food and shelters warm enough for winter.

The latest fighting has driven at least 48,500 people to flee their homes or shelters, and the number was rising rapidly, the United Nations warned.

Farnaz Fassihi contributed reporting from New York, and Rania Khaled from Cairo.

John Leung was an unlikely spy. In the small Oklahoma town where he lived, people knew him as a former restaurant owner and a father. In Houston, where he often traveled, they knew him as a political organizer in the city’s vibrant Chinese community.

And in China, they knew him as a benevolent patriot, a man who arranged musical performances and embraced official causes like unifying the mainland with Taiwan.

In fact, Mr. Leung was an informant for the F.B.I., gathering intelligence on China, according to two senior United States officials. That work landed him in Chinese custody in 2021, after he traveled to the mainland at the age of 75. He was later sentenced to life in prison, a first in decades for an American accused of espionage.

Mr. Leung was freed last Wednesday in a rare prisoner swap between Washington and Beijing. Six months shy of his 80th birthday, he was put on a plane to the United States with two other Americans who had been detained in China, along with three Uyghurs, members of an ethnic group that faces repression by the Chinese government.

In return, Washington released Xu Yanjun, a convicted Chinese spy who had been serving a 20-year sentence and Ji Chaoqun, 31, who had reported to Mr. Xu and was serving an eight-year sentence. A clemency order for a third Chinese national, Jin Shanlin, who had been in prison for possessing child pornography, was signed on the same day as an order for Mr. Xu. China said Washington also handed over a fugitive.

Mr. Leung had cultivated an image as a philanthropist, which brought him access to Chinese power circles. In Houston, he directed groups that promoted Beijing’s political interests. He attended Chinese state banquets. And he rubbed shoulders with senior Chinese officials, including its foreign minister, its ambassador and three consuls general to the United States.

But that carefully curated image was a ruse.

To piece together the story of Mr. Leung’s unusual trajectory from small-town restaurateur to prisoner in a high-stakes geopolitical dispute with China, The Times interviewed dozens of people who knew him, including relatives in the United States and Hong Kong, business associates in Houston and acquaintances in New York’s Chinatown. Reporters also drew on corporate records, archival materials and other documents.

Much remains unclear about Mr. Leung’s relationship with the F.B.I. China’s Ministry of State Security said that he was spying while in China, but U.S. officials said that Mr. Leung had not worked for the F.B.I. for years and that the bureau had discouraged him from making the trip.

Some of the pro-China groups Mr. Leung was involved with have been linked to organizations that have come under U.S. government scrutiny. One was affiliated with the National Association for China’s Peaceful Unification, which the Trump administration designated in 2020 as a foreign mission, accusing it of seeking “to spread Beijing’s malign influence in the United States.”

“Chinese intelligence operatives are known to use these organizations as cover for their clandestine operations,” said Dennis Wilder, a former U.S. intelligence analyst on China and a senior fellow at Georgetown University.

Mr. Leung’s work with such groups could have made him a useful informant, said Nigel Inkster, the former director of operations and intelligence for Britain’s Secret Intelligence Service. He described Mr. Leung as a likely “access agent,” with “no access to secrets himself but access to people who might have them.”

Christopher Wray, the F.B.I. director, has called Beijing the “biggest long-term threat to our economic and national security.”

China’s spy agency has publicized what it portrays as Mr. Leung’s treachery, saying that he “collected a significant amount of intelligence related to China.” The ministry said he lured Chinese officials into U.S. hotel rooms for “pornographic traps,” an allegation that former and current bureau officials said was false, explaining that the F.B.I. does not use such tactics.

The Chinese spy agency also released a video of Mr. Leung made while he was in custody, in which he expressed regret for what he had done. (Prisoners in China have in the past been coerced into making such televised confessions for propaganda purposes.)

Mr. Leung, who upon arriving in the United States was sent to an Army medical center outside San Antonio, could not be reached for comment. He was met there by a son, according to Nury Turkel, a lawyer who was there to welcome his mother, one of the Uyghurs released by Beijing. Calls and messages left for family members were not returned.

David Tang, a director with Mr. Leung of several pro-China groups in the Houston area, said he was happy to hear the news that Mr. Leung was back in the United States. He said he did not believe that he was a spy and that his release pointed to his innocence. “The mistake finally was corrected.”

An Arrest, and Charges Dropped

Mr. Leung was born in 1945 in Hong Kong’s New Territories, a largely mountainous, lush expanse of villages and farmland. He moved to New York in the 1970s, where he worked a low-level mailroom job at the United Nations while starting travel agencies in Chinatown with his brothers.

The travel business boomed. One agency, Leung Brothers Travel, had offices in New York and Toronto. It was the exclusive booking agent for Singapore Airlines, which often made it a necessary stop for people hoping to travel to Asia, said Tom Yiu, a longtime travel agent in Toronto.

New York’s Chinatown was roiled by crime, with Chinese gangs waging bloody turf wars, and Mr. Leung ran a side business selling guns, according to two longtime acquaintances. In 1980, his partner at a second travel agency was shot dead by two masked men while Mr. Leung crouched in the bathroom, according to acquaintances and to Chinese-language news reports from the time.

A few years later, he moved with his wife at the time, Kin Lan Ng, to Durant, a small college town in southeastern Oklahoma. The couple opened a Chinese restaurant in a strip mall, bought a modest home and raised three sons, according to property and ancestry records, and an interview with one son, Kit Leung.

In 1984, Mr. Leung was arrested in Durant in the attempted purchase of a .22-caliber pistol and a silencer from an undercover federal agent. He was charged with possession of an unregistered firearm, court records show.

Rick Musticchi, a former agent with the Bureau of Alcohol, Tobacco, Firearms and Explosives who sold Mr. Leung the gun and silencer, told The Times that he had approached Mr. Leung after getting a tip from an informant that he was involved in illegal activity and preparing to travel to China.

Mark F. Green, Mr. Leung’s lawyer on the case, said that prosecutors dropped charges after Mr. Musticchi did not show up to a hearing.

China’s spy agency said that U.S. intelligence operatives first contacted Mr. Leung soon after, in 1986, and formalized the relationship in 1989. The Times could not verify those allegations.

For a small-town restaurant owner, Mr. Leung soon developed unusually high-level connections inside China, which was opening to the West. He set up a group that promoted business and cultural ties between Oklahoma City and the southern Chinese city of Guangzhou, according to corporate records.

Mr. Leung also organized musical exchanges between Southeastern Oklahoma State University, The Juilliard School in New York and cities in China. He arranged for the Chinese classical pianist Li Yundi to perform in Oklahoma in 1999.

The performances he set up in China were sometimes disorganized, said Aaron Wunsch, a Juilliard pianist who joined several of them. Mr. Wunsch said he once arrived to find the piano wrapped in plastic and missing legs. But, he added: “He would talk in a genuine way about China and how he loved China and the U.S.”

Mr. Leung’s efforts earned him accolades inside China. In 2004, he was featured as one of 55 “outstanding overseas Chinese representatives” in People’s Daily, the Communist Party’s mouthpiece.

At a 2008 state banquet in Beijing celebrating the founding of China, he posed for a photo with Yang Jiechi, then the foreign minister, said Mr. Tang, who had also attended the event.

Li Liangzhou, a now-retired director of Guangzhou’s foreign affairs office, helped Mr. Leung organize many of the exchange trips. “He didn’t ask us about inside government information,” Mr. Li said in a phone interview in March. “We didn’t expect him to be a spy at all.”

Expanding Into Houston

In the mid-2000s, Mr. Leung began setting up pro-China groups in Houston, which was home to a large Chinese community and a Chinese consulate.

There, Mr. Leung drafted an alternative past. Mr. Tang, the other organizer of the pro-China groups, said he met Mr. Leung at a party in Houston, and they bonded by speaking Cantonese. Mr. Leung, who sometimes donated money to their groups, said he had come from wealth. He said he owned ranches in Oklahoma, sometimes showing up with farm eggs. He did not mention having owned a restaurant, despite the fact that his new friend was also a restaurateur, according to Mr. Tang.

The two joined forces in the Texas Council for the Promotion of China’s Peaceful Reunification, a group with links to the Washington, D.C.-based group the Trump administration later designated as a foreign mission.

Mr. Tang rejected the Trump administration’s characterization and said the group was set up to support American policy on China. He said he and Mr. Leung attended a 2018 protest against a stopover in Houston by Tsai Ing-wen, Taiwan’s president at the time.

Mr. Leung also became a director of the Chinese Civic Center in Houston, according to its tax filings. It serves the Chinese community and houses a separate service center that has come under scrutiny for suspected ties to Beijing. In 2023, the Justice Department accused two men of operating an “illegal overseas police station” out of a similar outpost in New York.

Xie Bin, a cybersecurity specialist in Houston, said he met Mr. Leung during this period at a mid-autumn festival event attended by Chinese diplomats. “He was the one who greeted everyone,” Mr. Xie said.

But Mr. Leung never found a home in Houston, said Mr. Tang, staying instead at a Ramada close to Chinatown.

The Chinese government’s efforts in Houston were becoming a focus for the F.B.I. Beginning in 2018, the bureau spent over a year investigating suspected intellectual property theft at Texas Medical Center by researchers with ties to China.

Relations deteriorated, and the Trump administration closed the Chinese consulate in Houston in July 2020, saying it was a hub of spying. Beijing responded by shuttering the U.S. consulate in Chengdu.

From a Life Sentence to a Surprise Release

In 2023, a Chinese court said Mr. Leung had been arrested two years earlier by state security agents from Suzhou, a city in Jiangsu Province. He had traveled to Jiangsu regularly for years, making inroads there with officials.

In China, where the top leader, Xi Jinping, has empowered security agencies to hunt down spies, Mr. Leung’s arrest and life sentence were hailed as a win.

In the United States, Mr. Leung’s case got little news coverage.

Kit Leung said in January at his home in Texas that Mr. Leung took him and a brother to Hong Kong to witness its handover to Chinese control in 1997 but that he and his father later became estranged. He said he learned about his imprisonment through news reports. Mr. Leung’s ex-wife, Ms. Ng, a New York resident, said she hadn’t spoken to him in years.

Another son moved into Mr. Leung’s house in Durant, neighbors said, and told them that his father had died. Reached there in January, that son, Carl Leung, declined to comment.

But under intense secrecy, the Biden administration was working out the contours of a swap with Beijing. During a global summit in Peru last month, President Biden discussed a potential trade with Mr. Xi.

When Mr. Leung and the two other American prisoners were released, they were met by Nicholas Burns, the U.S. ambassador to China, at the Beijing airport. He handed them their U.S. passports. President Biden and Secretary of State Antony J. Blinken separately called all three men when they landed in Alaska for refueling.

For Mr. Leung, it was the end of his time in Chinese custody — as well as the end of a ruse.

Edward Wong, Isabelle Qian, Chris Buckley, Keith Bradsher and Mattathias Schwartz contributed reporting. Jack Begg and Kirsten Noyes contributed research.

President Vladimir V. Putin of Russia and senior Kremlin officials “intentionally and directly” authorized a program of coerced fostering and adoption of Ukrainian children during the war in Ukraine, according to a Yale University report that was released on Tuesday.

The report provides strong new evidence for a war crimes case against Putin and other officials, the researchers said.

An investigation by Yale’s Humanitarian Research Lab identified 314 children from Ukraine who have been placed in a “systematic program of coerced adoption and fostering” since Russia’s full-scale invasion in February 2022, according to the report. It details evidence of direct orders from senior Russian officials, including Mr. Putin, to carry out the adoption program.

“It reveals a higher level of crime than first understood,” the Research Lab, which is part of the Conflict Observatory, a program supported by the U.S. Department of State, said in a statement.

Yale’s investigation could bolster the case against Mr. Putin and his commissioner for children, Maria Lvova-Belova, who were named in an arrest warrant issued by the International Criminal Court in March last year for their roles in the deportation of Ukrainian children to Russia.

The researchers cited what they said were verified leaked Russian documents that they said revealed how senior Russian officials had worked with officials in the occupied regions of Ukraine to carry out the program. The report says the Russian president’s office provided direct financial support and other assets for the program.

The treatment of the Ukrainian children may constitute a war crime or crimes against humanity, and could even support a case of genocide under the Rome Statute of the International Criminal Court, the Research Lab said.

Ukrainian officials and members of the Yale research team are scheduled to appear before a special meeting of the United Nations Security Council on Wednesday to explain their findings, the statement said.

The Kremlin has denied committing war crimes, and maintains that the adoptions are a patriotic and humanitarian effort to help abandoned children. It has also noted that is not a party to the I.C.C. and therefore has no obligations under it.

The State Department has condemned Russia’s treatment of Ukrainian children in the war, and in August announced new sanctions on several entities and individuals over the “forced deportation, transfer and confinement of Ukraine’s children.”

In addition to Mr. Putin and Ms. Lvova-Belova, the Yale report names four other Russian officials over roles in the deportation, fostering and adoption of Ukrainian children: Anna Kuznetsova, a senior official in Mr. Putin’s United Russia party; Sergei Kravtsov, Russia’s education minister; and the heads of regional pro-Russian administrations in Ukraine’s Donetsk and Luhansk Provinces.

The evidence gathered by the Yale researchers concerns 314 children aged 2 to 17, from Donetsk and Luhansk Provinces in eastern Ukraine, many of whom were removed from two well-known boarding schools. The group also includes one child from the occupied city of Mariupol.

The report said it had established with high confidence the Ukrainian origin of the children, independent of other investigations and news reports. The researchers said they had used multiple sources of information to corroborate information, including leaked Russian documents and communications, satellite images, geolocation techniques and metadata analysis.

That investigative work aimed to establish both the logistics involved in moving the children and the chain of command behind the program, it said.

Donetsk and Luhansk Provinces have been largely under Russian control since 2014, when Russian-backed separatists first seized power there. Russia declared the annexation of the provinces in 2022, and moved to integrate their Ukrainian institutions into the Russian system.

Some of the 314 children have been placed into Russian families, and others were listed on a Russian database for fostering and adoption, Yale’s report said. The university did not release the children’s identities but said it had passed their names and circumstances to the international court and the Ukrainian authorities.

While some of the children are orphans or had previously been removed from the care of their parents, some according to database files had parents in Ukraine who have been deprived of their parental rights by Russia’s actions, the report said. At least three children have been placed in families of Russian officials or Russian military families, it said.

The researchers said they had tracked the movement of each of the 314 children to temporary facilities in Russia at midpoints in their deportation and their dispersal after that across 21 regions of Russia. The report said that Russian military planes were used in the transporting of the children, which was widely reported in Russian news footage and photographs.

The researchers said that they had documentation that at least 67 of the children had been naturalized as Russian citizens, and that the true number of such naturalizations was probably much higher.

The Yale researchers said they had not been able to pursue all leads or to find and identify all of the children on Russian placement databases. They said there were thousands more Ukrainian children in Russia who had yet to be identified.

The report also accused the Russian authorities of working to conceal the origin and whereabouts of the Ukrainian children. After the international court issued its arrest warrants, Russia removed much of the evidence from relevant websites, the report said.

“Russia engaged in acts of deception to conceal the full scope of this program and related activities,” the report said. “Most critically, children taken from Ukraine are fundamentally presented in Russia’s databases as if they were from Russia.”