The passenger plane with 181 people onboard skidded on the runway at a high speed and slammed into a wall before exploding into flames.

Two crew members were rescued alive from the tail of the burning plane, but over the ensuing hours on Sunday, grim news trickled out to anxious relatives at Muan International Airport, in southwestern South Korea.

By late Sunday, all of the remaining 179 people onboard were confirmed dead, making the crash of the plane — flown by the popular low-cost carrier Jeju Air — the worst aviation disaster involving a South Korean airline in nearly three decades and the worst ever on South Korean soil.

Sunday’s crash was the deadliest worldwide since that of Lion Air Flight 610 in 2018, when all 189 people on board died as the plane plunged into the Java Sea, according to reports from the International Civil Aviation Organization, a United Nations agency.

Officials were investigating what caused the Jeju Air flight to crash-land, including why its landing gear appeared to have malfunctioned and whether the plane had been struck by birds.

As speculation swirled about the cause of the crash, hundreds of family members of passengers endured the painful wait for news of their loved ones returning home from a trip abroad. Wails and screams filled the Muan airport on Sunday afternoon. A young woman comforted an older woman weeping about her son. Two crying women embraced each other.

By Sunday evening, only 65 of the dead could be identified through their fingerprints and other means, officials said. A dozen bodies were so badly damaged that officials could not immediately identify their gender. Those who were identified included a 23-year-old flight attendant and a 78-year-old male passenger.

Jang Gu-ho, 68, sat stoically in the arrivals hall next to his teary-eyed wife after rushing from his home in the nearby city of Mokpo. He said five of his relatives had been on the plane returning from a vacation: his wife’s sister, her daughter, son-in-law and two grandchildren.

“We’re thunderstruck,” he said.

In a closed area of the airport, officials were working to identify the bodies they recovered from the crash site. When officials posted on the walls of the arrivals hall the names of those confirmed dead, people rushed to check the lists.

The disaster left South Korea in shock at a time when the country was grappling with a political crisis unleashed by President Yoon Suk Yeol’s ill-fated and short-lived declaration of martial law and his subsequent impeachment this month. Deputy Prime Minister Choi Sang-mok, an unelected official, rushed to the scene to deal with his biggest challenge since he took office as acting president on Friday.

The plane crash was especially shocking for the country because it has had no major aviation disaster after a spate of deadly air accidents in the 1990s and earlier. In the last major aviation accident involving a South Korean airline, a Korean Air jet slammed into a hill in Guam, a U.S. territory in the western Pacific, in 1997, killing 229 of the 254 people on board.

It also appeared to have been the first fatal one for Jeju Air, which was established in 2005 and flies to dozens of countries in Asia. Kim E-bae, the chief executive of Jeju Air, bowed as he publicly apologized for the crash. He said that the exact cause of the crash was unclear.

The plane, Jeju Air Flight 7C2216, a Boeing 737-800 jet, had taken off from Bangkok with 175 passengers and six crew members. All passengers were South Koreans, except for two Thai nationals. The jet was landing at Muan, in southwestern South Korea, when it ran into trouble.

Footage of the accident showed a white-and-orange plane speeding down a runway on its belly until it rammed into a barrier at the end of the runway, exploding into a fireball. Local news media cited witnesses describing the sound of the explosion and published photographs of large plumes of black smoke over the site.

The plane had broken into so many pieces that only its tail was immediately identifiable, said Lee Jeong-hyeon, an official in charge of search and rescue operations at the scene. The two crew members who survived had been rescued from the tail section.

“We could not recognize the rest of the fuselage,” Mr. Lee said.

As the death toll climbed, details of what happened in the final moments before the crash began to emerge.

As the plane was preparing to land, the airport warned the pilots about a potential bird strike, said Ju Jong-wan, a director of aviation policy at the Ministry of Land, Infrastructure and Transport. Around this time, witnesses heard loud explosion-like sounds, MBC-TV reported. The channel broadcast footage showing flames trailing briefly from one of the plane’s engines.

The plane issued a mayday alert shortly after the warning from the airport, then crash-landed, Mr. Ju said. The pilot aborted his first attempt at landing and with permission from the control tower, was landing from the opposite direction when the disaster happened, officials said. Planes were allowed to land from both directions at the airport, they said.

The muddy tidal flats near Muan and much of the west coast of the Korean Peninsula are favorite resting places for migrant birds. Photographs in local media showed flocks of birds flying near the airport on Sunday.

Evidence suggested that the aircraft encountered a flock of birds during its approach, leading to suspected bird ingestion into the engines, said Marco Chan, a senior lecturer in aviation operations at the U.K.-based Buckinghamshire New University.

The damage may have caused a hydraulic system failure, which could explain the inability to deploy the landing gear, Mr. Chan said in an analysis emailed by his university.

The plane also did not appear to have activated its wing flaps, said Keith Tonkin, the managing director of Aviation Projects, an aviation consulting company in Brisbane, Australia, who reviewed video of the crash. That meant it was traveling faster than normal landing speed when it belly flopped on the runway, he said.

Aviation experts said investigations into the causes of crashes can take years.

At the Muan airport, as officials told the crowd that they had confirmed the identities of some of the people, and announced their names, some began to cry. Others grew angry and raised their voices in frustration: “Speak up!” “Print out the names!” Several hours after the crash, people expressed frustration that they had to wait so long for news about their relatives. “Let us have the list so we can at least find a hospital!” one woman shouted.

People crowded around an official to check if their relatives were on a list of those confirmed dead. Some relatives had given DNA samples to officials at the airport to help identify the bodies.

In the departures hall, temporary tents were set up on Sunday evening for families of the plane’s passengers and crew. Outside the airport, cars lined up to enter the packed parking lots. Some parked on the shoulders of the roads leading to the terminal, and people continued to stream into the airport through the evening.

Six hours after they dashed to the airport, Mr. Jang and his wife were still waiting for their relatives to be identified.

“I’m expecting it to be a long night,” he said.

Reporting was contributed by Yan Zhuang, River Akira Davis, Niraj Chokshi and Sui-Lee Wee.

Right up until he was assassinated, Hassan Nasrallah did not believe that Israel would kill him.

As he hunkered inside a Hezbollah fortress 40 feet underground on Sept. 27, his aides urged him to go to a safer location. Mr. Nasrallah brushed it off, according to intelligence collected by Israel and shared later with Western allies. In his view, Israel had no interest in a full-scale war.

What he did not realize was that Israeli spy agencies were tracking his every movement — and had been doing so for years.

Not long after, Israeli F-15 jets dropped thousands of pounds of explosives, obliterating the bunker in a blast that buried Mr. Nasrallah and other top Hezbollah commanders. The next day, Mr. Nasrallah’s body was found in an embrace with a top Iranian general based in Lebanon. Both men died of suffocation, the intelligence found, according to several people with knowledge of it.

The death of Hezbollah’s feared leader, who for decades commanded a Lebanese militia in its fight against the Israeli state, was the culmination of a two-week offensive. The campaign combined covert technological wizardry with brute military force, including remotely detonating explosives hidden in thousands of pagers and walkie-talkies used by Hezbollah, as well as a withering aerial bombardment with the aim of destroying thousands of missiles and rockets capable of hitting Israel.

It was also the result of two decades of methodical intelligence work in preparation for an all-out war that many expected would eventually come. A New York Times investigation, based on interviews with more than two dozen current and former Israeli, American and European officials who spoke on the condition of anonymity to discuss classified operations, reveals just how extensively Israeli spies had penetrated Hezbollah. They recruited people to plant listening devices in Hezbollah bunkers, tracked meetings between one top commander and his four mistresses, and had near constant visibility into the movements of the militia group’s leaders.

It is a story of breakthroughs, as in 2012 when Israel’s Unit 8200 — the country’s equivalent of the National Security Agency — stole a trove of information, including specifics of the leaders’ secret hide-outs and the group’s arsenal of missiles and rockets.

There were stumbles, as in late 2023 when a Hezbollah technician got suspicious about the batteries in the walkie-talkies.

And there were scrambles to save their efforts, as in September, when Unit 8200 collected intelligence that Hezbollah operatives were concerned enough about the pagers that they were sending some of them to Iran for inspection.

Worried that the operation would be exposed, top intelligence officials persuaded Prime Minister Benjamin Netanyahu of Israel to give the order to detonate them, setting in motion the campaign that culminated in the assassination of Mr. Nasrallah.

Israel’s decimation of Hezbollah was a significant victory for a country that, one year earlier, had suffered the greatest intelligence failure in its history, when Hamas-led fighters invaded it on Oct. 7, 2023, killed more than 1,200 people and took 250 hostages.

The Hezbollah campaign, part of a broader war that has killed thousands of people in Lebanon and displaced more than a million, defanged one of Israel’s greatest adversaries and dealt a blow to Iran’s regional strategy of arming and funding paramilitary groups bent on Israel’s destruction. The weakening of the Iran-led axis reshaped the dynamics in the Middle East, contributing to the fall of the Assad regime in Syria.

The contrast between Israel’s approaches to Hezbollah and to Hamas is also stark and devastating. The intense intelligence focus on Hezbollah shows that the country’s leaders believed that the Lebanese militia group posed the greatest imminent threat to Israel. And yet it was Hamas in the Gaza Strip, a group Israeli intelligence believed had neither the interest nor the abilities to attack Israel, that launched a surprise attack and caught the nation unprepared.

Israel was in a standoff with Mr. Nasrallah and his top commanders of Hezbollah, the “Party of God,” for decades, and Israeli intelligence assessments have concluded that it will take years, possibly more than a decade, for the group to rebuild after their deaths. The group of leaders now in charge has far less combat experience than the earlier generation.

And yet the new leaders, like Hezbollah’s founders, are driven by a central animating principle: conflict with Israel.

“Hezbollah can’t continue to get support and funding from Iran without being in a war against Israel. That’s the raison d’être for Hezbollah,” said Brig. Gen. Shimon Shapira, a former military secretary for Mr. Netanyahu and the author of “Hezbollah: Between Iran and Lebanon.”

“They will rearm and rebuild,” he said. “It’s only a matter of time.”

Building a Network of Sources

The 2006 war between Israel and Hezbollah was a bloody stalemate. Israel withdrew from Lebanon after 34 days of fighting, which began after Hezbollah kidnapped and killed two Israeli soldiers. The war, which did not achieve Israel’s objectives, had been something of a humiliation, forcing an investigation panel, resignations of top generals and a reckoning inside Israel’s security apparatus about the quality of its intelligence.

But operations during the war, based on Israeli intelligence gathering, formed the foundation for the country’s later approach. One operation planted tracking devices on Hezbollah’s Fajr missiles that gave Israel information about munitions hidden inside secret military bases, civilian storage facilities and private homes, according to three former Israeli officials. In the 2006 war, the Israeli Air Force bombed the sites, destroying the missiles.

In the years after the war, Mr. Nasrallah projected confidence that Hezbollah could win another conflict against Israel, likening the nation to a spider web — menacing from afar but a threat that could be easily brushed aside.

As Hezbollah rebuilt, the Mossad, Israel’s foreign intelligence service, expanded a network of human sources inside the militia, according to 10 current and former American and Israeli officials.

Specifically, the Mossad recruited people in Lebanon to help Hezbollah build secret facilities after the war. The Mossad sources fed the Israelis information about the locations of hide-outs and assisted in monitoring them, two officials said.

The Israelis generally shared Hezbollah intelligence with the United States and European allies.

A significant moment came in 2012, when Unit 8200 obtained a trove of information about the specific whereabouts of Hezbollah leaders, their hide-outs and the group’s batteries of missiles and rockets, according to five current and former Israeli defense and European officials.

That operation raised confidence within Israeli intelligence agencies that — should Mr. Netanyahu make good on threats to attack Iran’s nuclear sites — the Israeli military could help neuter Hezbollah’s ability to retaliate.

Mr. Netanyahu visited the Tel Aviv headquarters of Unit 8200 shortly after the operation. During the visit, the head of Unit 8200 made a show by printing out the trove of information, producing a tall stack of paper. Standing next to the material, he told Mr. Netanyahu, “You can now attack Iran,” according to two current and former Israeli defense officials with knowledge of the meeting.

Israel did not attack.

During the years that followed, Israeli spy agencies worked to refine the intelligence gathered from the earlier operation to produce information that could be used in the event of a war with Hezbollah.

According to two Israeli defense officials with knowledge of the intelligence, when the 2006 war ended, Israel had “target portfolios” for just under 200 Hezbollah leaders, operatives, weapons caches and missile locations. By the time Israel launched its campaign in September, it was tens of thousands.

Turning Pagers Into Deadly Devices

To gain an advantage in an eventual war with Hezbollah, Israel also developed plans to sabotage the militia from within. Israel’s Unit 8200 and Mossad championed a plan to supply Hezbollah with booby-trapped devices that could be detonated at a future date, according to six current and former Israeli defense officials.

Within the Israeli intelligence community, the devices were known as “buttons” that could be activated at Israel’s moment of choosing.

Designing and producing the buttons was relatively straightforward. Israeli engineers mastered placing PETN explosives within the batteries of electronic devices, turning them into small bombs.

The more difficult operation fell to the Mossad, which for nearly a decade tricked the group into buying military equipment and telecommunication devices from Israeli shell companies.

In 2014, Israel seized an opportunity when the Japanese technology company iCOM stopped producing its popular IC-V82 walkie-talkies. The devices, originally assembled in Osaka, Japan, were so popular that replicas were already being made across Asia and sold in online forums and in black market deals.

Unit 8200 discovered that Hezbollah was specifically searching for the same device to equip all of its frontline forces, according to seven Israeli and European officials. They had even designed a special vest for their troops with a chest pocket tailored for the device.

Israel began manufacturing its own replicas of the walkie-talkies with small modifications, including packing explosive material into their batteries, according to eight current and former Israeli and American officials. The first Israeli-made replicas arrived in Lebanon in 2015 — and more than 15,000 were eventually shipped, some of the officials said.

In 2018, a female Israeli Mossad intelligence officer drafted a plan that would use a similar technique to implant explosive material into a pager battery. Israeli intelligence commanders reviewed the plan, but determined that Hezbollah’s use of pagers was not widespread enough, according to three officials. The plan was shelved.

Over the next three years, Israel’s increasing ability to hack into cellphones left Hezbollah, Iran and their allies increasingly wary of using smartphones. Israeli officers from Unit 8200 helped fuel the fear, using bots on social media to push Arabic-language news reports on Israel’s ability to hack into phones, according to two officers in the agency.

Worried about smartphones being compromised, Hezbollah’s leadership decided to expand its use of pagers. Such devices allowed them to send out messages to fighters but did not reveal location data nor have cameras and microphones that could be hacked.

As it did, Hezbollah began looking for pagers hardy enough for combat conditions, according to eight current and former Israeli officials. Israeli intelligence officers reconsidered the pager operation, and worked to build a network of shell companies to hide their origins and sell the products to the militia.

Israeli intelligence officers targeted the Taiwanese brand Gold Apollo, well known for pagers.

In May 2022, a company called BAC Consulting was registered in Budapest. One month later, in Sofia, Bulgaria, a company called Norta Global Ltd. was registered to a Norwegian citizen named Rinson Jose.

BAC Consulting bought a licensing agreement from Gold Apollo to manufacture a new pager model known as the AR-924 Rugged. It was bulkier than the existing Gold Apollo pagers, but it was promoted as waterproof and with a longer-lasting battery life than competitors’ devices.

The Mossad oversaw production of the pagers in Israel, according to Israeli officials. Working through intermediaries, Mossad agents began marketing the pagers to Hezbollah buyers and offered a discounted price for a bulk purchase.

The Mossad presented the gadget, one without any hidden explosives, to Mr. Netanyahu during a meeting in March 2023, according to two people with knowledge of the meeting. The prime minister was skeptical about their durability, and asked David Barnea, the Mossad chief, how easily they might break. Mr. Barnea assured him they were sturdy.

Not convinced, Mr. Netanyahu abruptly stood up and threw the device against the wall of his office. The wall cracked, but the pager did not.

The Mossad front company shipped the first batch of pagers to Hezbollah that fall.

Conducting War Games

The pager operation was not fully in place in October 2023, when the Hamas-led attacks ignited a fierce debate within the Israeli government about whether Israel should launch a full-scale war against Hezbollah.

Some, including Defense Minister Yoav Gallant, argued for striking at Hezbollah, which began launching missiles at Israel on Oct. 8 in solidarity with Hamas. It was an opportunity, he said, to deal with the “hard enemy” of Hezbollah before turning to what he considered the less difficult enemy of Hamas, according to five Israeli officials familiar with the meetings.

After a phone call with President Biden on Oct. 11, 2023, Mr. Netanyahu, along with his newly formed war cabinet, decided for the time being against opening another front with Hezbollah, effectively ending high-level debate about the topic for months.

Even as Israel focused on Hamas, military and intelligence officials continued to refine plans for an eventual war with Hezbollah.

Israeli intelligence analysts, who were constantly monitoring the use of the devices, discovered a potential problem with the operation. At least one Hezbollah technician began to suspect that the walkie-talkies might contain hidden explosives, according to three Israeli defense officials. Israel dealt with it swiftly this year, killing the technician with an airstrike.

For nearly a year, Israeli intelligence and the air force also ran roughly 40 war games built around killing Mr. Nasrallah and other senior Hezbollah leaders, said two Israeli officials. They wanted to be able to target them at the same time, even if they were not in the same place.

Along the way, Israel collected mundane and intimate details about Hezbollah commanders, including the identities of the four mistresses of Fuad Shukr, a founding member of Hezbollah long ago identified by the U.S. government as one of the planners of the 1983 bombing of the barracks in Beirut, Lebanon, that killed 241 American Marines.

At one point this year, apparently feeling uncomfortable about his situation, Mr. Shukr sought assistance from Hezbollah’s highest religious cleric to marry all four women, according to two Israeli officials and a European official. The cleric, Hashem Safieddine, arranged four separate phone-based wedding ceremonies for Mr. Shukr.

The simmering conflict boiled over this summer, when a Hezbollah rocket attack in July killed a dozen Israelis, including schoolchildren, in Majdal Shams, a town in the Golan Heights.

Israel responded days later with an airstrike in Beirut that killed Mr. Shukr. It was a provocative step to take, to assassinate a top commander of Hezbollah’s forces.

‘Use It or Lose It’

After the back-and-forth attacks, the debate renewed inside Israel’s government about opening a “northern front” against Hezbollah. The Israeli military and the Mossad drew up different strategies for a campaign against Hezbollah, according to four Israeli officials.

In late August, Mr. Barnea, the Mossad chief, wrote a secret letter to Mr. Netanyahu, according to a senior Israeli defense official. The letter advocated a two-to-three-week campaign that included eliminating more than half of the group’s missile abilities and destroying installations within about six miles of the Israeli border. At the same time, senior military officials began their own effort to lobby Mr. Netanyahu to intensify a campaign against Hezbollah.

New intelligence disrupted the planning. Hezbollah operatives had become suspicious that the pagers might be sabotaged, according to several officials.

On Sept. 11, intelligence showed that Hezbollah was sending some of the pagers to Iran for examination, and Israeli officials knew it was only a matter of time before the covert operation would be blown.

On Sept. 16, Mr. Netanyahu met with top security chiefs to weigh whether to detonate the pagers in a “use it or lose it” operation, according to four Israeli security officials. Some opposed it, saying it might prompt a full Hezbollah counterattack and possibly a strike by Iran.

Mr. Netanyahu ordered the operation. The following day, at 3:30 p.m. local time, the Mossad ordered an encrypted message to be sent to thousands of the pagers. Seconds later, the pagers detonated.

At the time the pagers exploded, Mr. Jose, the Norwegian who was the head of one of the Mossad front companies, was attending a technology conference in Boston.

Within days, Mr. Jose was identified in news articles as a participant in the operation, and the Norwegian government announced that it wanted him back in Norway for questioning.

Israeli officials secretly pressured the Biden administration to ensure that Mr. Jose could leave the United States without going back to Norway, according to one Israeli and one American official.

Israeli officials would not disclose Mr. Jose’s location. One senior Israeli defense official said only that he was in a “safe place.”

Approving an Assassination

After the pager operation, the Netanyahu government, with the support of high-ranking defense officials, opted for all-out war, a campaign marked by a series of escalations.

The day after detonating the pagers, the Mossad blew up the walkie-talkies, most of which were still in storage because Hezbollah leaders had not yet mobilized fighters for a battle against Israel.

In all, dozens of people were killed by the pager and walkie-talkie explosions, including several children, and thousands were wounded. Most of the casualties were Hezbollah operatives, sowing chaos among the top ranks of the group.

Days after, on Sept. 20, Israeli jets struck a building in Beirut where commanders of Hezbollah’s elite Radwan Force were meeting in a bunker, killing several of them along with Ibrahim Aqeel, the head of Hezbollah’s military operations.

On Sept. 23, the Israeli Air Force conducted a major campaign, hitting more than 2,000 targets aimed at Hezbollah’s stores of medium and long-range missiles.

The most consequential decision remained: whether or not to kill Mr. Nasrallah.

As senior Israeli officials debated, intelligence agencies received new information that Mr. Nasrallah planned to move to a different bunker, one that would be far more difficult to hit, according to two Israeli defense officials and a Western official.

On Sept. 26, with Mr. Netanyahu set to fly to New York for a meeting of the United Nations General Assembly, the prime minister gathered with his top political, intelligence and military advisers to discuss approving the assassination. They also had to decide whether to tell the Americans in advance.

Mr. Netanyahu and other top advisers opposed notifying the Biden administration. They believed that U.S. officials would push back against the strike, but that regardless, the United States would come to Israel’s defense in case Iran retaliated.

They agreed to keep the Americans in the dark.

Mr. Netanyahu approved the assassination the next day, after he landed in New York and only hours before standing at the podium at the United Nations.

In his speech, he spoke about the grip that Hezbollah had over Lebanon. “Don’t let Nasrallah drag Lebanon into the abyss,” he told the presidents and prime ministers gathered.

Soon after, the Israeli F-15 jets above Beirut dropped thousands of pounds of explosives.

Adam Goldman contributed reporting from Washington.

The leader of Azerbaijan directly blamed Russia on Sunday for the crash of an Azerbaijan Airlines passenger jet last week, calling on Moscow to accept responsibility and offer compensation to victims.

President Ilham Aliyev said in an interview with Azerbaijan’s national broadcaster that a vague apology issued by President Vladimir V. Putin of Russia a day earlier would not suffice to preserve friendly relations between the two former Soviet states.

The Embraer 190 airliner was traveling from Baku, Azerbaijan, to Grozny in southern Russia on Wednesday, but was diverted from its path after encountering interference with its navigation systems and impact with external objects, according to Azerbaijan’s government. The plane crashed in Kazakhstan soon after, resulting in the deaths of 38 of the 67 people on board, more than half of them Azerbaijani citizens.

Azerbaijani and U.S. officials, as well as international aviation experts, had said they believed that the plane was most likely shot down by a Russian air defense missile. Moscow, however, has not admitted responsibility.

Mr. Aliyev’s comments on Sunday offered the most direct rebuke yet of Kremlin’s position on the crash.

“We can clearly say today that the plane was shot down by Russia,” Mr. Aliyev said in the interview, according to a summary published in English by Azerbaijan’s state news agency. “First, the Russian side must apologize to Azerbaijan. Second, it must acknowledge its guilt. Third, those responsible must be punished.”

Mr. Aliyev added that Moscow had met only the first condition thus far.

On Saturday, Mr. Putin broke the Kremlin’s three-day silence on the crash. He called Mr. Aliyev and apologized, without directly acknowledging Russian responsibility, according to summaries of the call published by the two governments.

“Vladimir Putin offered his apologies that the tragic incident took place in the Russian airspace,” the Kremlin said in its summary.

Russia said that as the plane approached Grozny, Russian air defenses had begun to repulse an attack by Ukrainian drones on the airport there and others nearby.

Ukraine, which has targeted Grozny with drones in recent weeks, has not confirmed or denied that such an attack took place.

Mr. Aliyev said in the television interview that the airliner was hit by accident. He criticized, however, Moscow’s tardy and noncommittal response, which initially attempted to blame the crash on fog or birds.

“Unfortunately, for the first three days, we heard nothing from Russia except for some absurd theories,” Mr. Aliyev said.

Analysts said that Mr. Aliyev had taken a strong stand on Russia because he himself accepted responsibility and offered compensation when Azerbaijan’s military mistakenly shot down a Russian military helicopter in 2020, killing two Russian service members.

“Azerbaijan now expects similar actions from Moscow,” said Zaur Shiriyev, a Baku-based foreign policy expert at the Carnegie Endowment for International Peace, a policy research organization.

It remains unclear if Mr. Aliyev’s strongly worded demands to the Kremlin signaled a cooling of relations between the two countries, or were meant primarily to satisfy a domestic audience.

Azerbaijan has assumed a neutral position on the war in Ukraine, benefiting from growing trade with Russia while exploiting Moscow’s distraction to pursue its interests in the Caucasus. Analysts have said the country has little incentive to let the crash derail this beneficial status quo with Moscow.

Some analysts have said that Mr. Putin could resolve the flare-up of tensions with Mr. Aliyev, a fellow autocrat with longstanding ties to Moscow elites, by striking a private deal.

Such a scenario would spare Mr. Putin the political cost of assuming responsibility for the crash but it would be likely to breed long-term resentment against Russia among the Azerbaijani public, the analysts say.

The Kremlin did not immediately comment on Mr. Aliyev’s demands on Sunday.

Milana Mazaeva contributed reporting from Istanbul.

For years, the Houthis were the enemy most Israelis didn’t know they had.

Now the Iranian-backed militia that controls much of northern Yemen, over a thousand miles from Israel, is keeping them up at night — literally — with a string of attacks on Israeli soil. And challenged by a lack of precise intelligence on the whereabouts of the group’s leaders and weapons stores, analysts say, Israel is struggling to stop them.

After months of sporadic missile and drone launches toward Israel in solidarity with Hamas, their Palestinian ally in Gaza, the Houthis recently escalated a campaign against Israel, launching ballistic missiles toward it almost nightly over the past week.

The militia appeared undeterred even after Israel’s war planes on Thursday carried out their fourth and most brazen round of retaliatory strikes in Yemen, damaging the international airport in the capital, Sana, and other infrastructure.

The Houthis then fired a missile toward Tel Aviv before dawn on Friday and another around 2 a.m. on Saturday, setting off air raid sirens. Both missiles were intercepted, but the sirens sent millions of people running into bomb shelters in their pajamas.

The militia has withstood years of bombardment by a Saudi-led coalition that tried to oust it, pressure from Emirati-backed forces supporting the internationally recognized government in Yemen, and American and British strikes in retaliation for Houthi attacks on shipping in the Red Sea. Now it is displaying a similar resilience against Israel.

“We have a problem,” said Zohar Palti, a former director of intelligence in Mossad, Israel’s foreign intelligence service, and a former director of policy in Israel’s Ministry of Defense. Israel, on its own, does not have a “patent” for solving the problem, he added.

Israel’s security establishment has never prioritized Yemen and has not expended efforts in gathering intelligence on the Houthis over the years, experts say.

Israel had “too many balls in the air,” Mr. Palti said, citing Iran and its nuclear program, Hamas militants in Gaza, the Iran-backed Hezbollah militia in Lebanon and dealing with counterterrorism the world over.

“It’s a matter of investment,” he said. “It may take days, weeks or months, but in the end we will bring the intelligence.”

Still, Mr. Palti added, it is unlikely to be Israel’s top priority, with many preferring to invest in thwarting Iran’s nuclear ambitions.

The Houthis began firing on Israel soon after the Hamas-led assault on the country on Oct. 7, 2023, which prompted the war in Gaza. The militants said they were acting in solidarity with Hamas and Palestinians in general. The Houthis also tried to blockade Israel by launching missiles and drones at cargo vessels crossing the Red Sea, one of the world’s busiest shipping lanes, significantly disrupting international trade.

At first, the threat to Israel appeared distant compared with that posed by Hamas on its southern border and Hezbollah on its northern one. Houthi attack drones would take about 10 hours to reach Israel’s southern port of Eilat. They and the occasional ballistic missile fired from Yemen were often intercepted far from Israel’s territory or airspace with the help of international forces in the Persian Gulf region and were regarded by many Israelis as a somewhat bizarre nuisance.

But a drone fired by the Houthis in July took a different route. Flying in from the west over the Mediterranean coast, it evaded Israel’s defenses and slammed into an apartment building in Tel Aviv, the country’s commercial center, killing one man and wounding several other people. Israel struck back the next day with its first barrage of airstrikes on Yemen, bombing the vital Red Sea port of Hudaydah, which is controlled by the Houthi militia.

The long-distance exchanges have continued even as Israel’s multipronged battles in the region appear to be winding down. Hamas’s military capabilities have been severely diminished, a cease-fire between Israel and Hezbollah went into effect in late November and the Assad government in Syria has fallen. But the Houthis have begun escalating attacks on Israel, vowing to continue until Israel ends the war in Gaza.

The warhead of one intercepted missile badly damaged a school in a Tel Aviv suburb this month, landing at night when the building was empty. Another missile got through and struck a playground in Tel Aviv, damaging the surrounding apartment buildings and slightly wounding 16 people.

Israel’s leaders have since ratcheted up their tough talk.

“The Houthis, too, will learn what Hamas, Hezbollah, the Assad regime and others have learned,” Prime Minister Benjamin Netanyahu said on Wednesday.

On Thursday after the Israeli strikes, Mr. Netanyahu said in an interview with an Israeli TV station of the Houthis: “We are just getting started with them.” Israel Katz, the Israeli defense minister, has vowed to hunt down the Houthi leaders.

Still, analysts note that it took the United States a decade to track down and kill Osama bin Laden, Al Qaeda’s founder, and it took Israel more than a year after the Oct. 7 attack to close in on and kill Yahya Sinwar, the leader of Hamas, in Gaza, a tiny coastal enclave. If Israel knew where the Houthi leaders were, it would probably have killed them already, the analysts say.

In addition to the airport in Sana, a Houthi stronghold, the Israeli military also struck the Hezyaz and Ras Kanatib power stations and infrastructure in the ports of Al-Hudaydah, Salif and Ras Kanatib on Yemen’s western coast. Israel described the targets as “military infrastructure used by the Houthi terrorist regime for its military activities.”

At least four people were killed and 21 others wounded in the attack on Thursday, according to the Saba state news agency, citing Yemen’s Health Ministry. The director general of the World Health Organization, Dr. Tedros Adhanom Ghebreyesus, who was at the airport waiting to board a plane at the time, said in a social media post that the air traffic control tower, the departure lounge and the runway were damaged.

But analysts say that damaging Yemen’s national infrastructure is not likely to stop the Houthis from attacking Israel.

“They took everything by force, they don’t rule by consensus, they don’t care and they are willing to go very, very far,” said Farea Al-Muslimi, a Yemeni research fellow at Chatham House, a London-based research institute, of the Houthis.

With the leadership of Hezbollah and Hamas decimated and the Assad government gone, the Houthis have “jumped into the front carriage of the axis-of-resistance train,” Mr. al-Muslimi said, referring to the Iranian-backed forces in the region that have been fighting Israel.

Since Oct. 7, 2023, he said, the Houthis have cemented their presence as a global actor, and they are likely to hold out in their fight against Israel until there is a cease-fire in Gaza.

Israeli officials and analysts are now arguing that the Houthi challenge is not only Israel’s problem, particularly given the distance between Israel and Yemen.

Noting a “stark increase” in Houthi missiles fired at Israel, Lt. Col. Nadav Shoshani, a spokesman for the Israeli military, said on Saturday, “The Houthis are a global problem.”

Israel acts in close coordination with the American forces in the region. U.S. Central Command forces have attacked Houthi targets in Yemen in recent days, and the missile fired at Israel from Yemen early Friday was intercepted with the help of the American THAAD missile defense system that was recently deployed in Israel.

Assaf Orion, a retired Israeli brigadier general and an international fellow at the Washington Institute for Near East Policy, noted that a campaign against the Houthis in Yemen is not, so far, one of the war goals approved by the Israeli cabinet since Hamas attacked last year.

“There are no simple solutions to complex problems,” he said. “Ultimately, this is not just a face-off between Israel and the Houthis but part of a regional and international struggle.”

A former soccer star and conservative critic of the West was sworn in on Sunday as the new president of Georgia, a strategically important republic in the middle of the Caucasus, replacing a head of state who vowed to continue fighting to steer the country closer to Europe.

Mikheil Kavelashvili, 53, was sworn in as president in a hall of Parliament that had many empty seats as representatives from four opposition parties refused to enter it after an election in October that they denounced as rigged.

The parliamentary elections and the inauguration of a conservative president known for his criticisms of Western governments represented a watershed moment for Georgia. Traditionally regarded as a pro-Western trailblazer among states that emerged after the Soviet collapse, Georgia, a country of 3.6 million people, is now widely seen as moving closer to Russia and China.

During his inauguration, Mr. Kavelashvili said that now Georgians “must approach existing challenges with caution, analyze the threats” and “make decisions not based on emotions but as a result of careful thought.”

The standoff between Georgia and its former Western backers deepened on Friday when the United States announced that it was imposing sanctions on Bidzina Ivanishvili, a reclusive oligarch and founder of the Georgian Dream party, who is widely seen as Georgia’s shadow leader.

Mr. Kavelashvili’s inauguration took place amid a political crisis in Georgia triggered by the parliamentary election, which the opposition and some European officials regard as fraudulent. The already tense crisis deepened at the end of November when Georgia’s prime minister announced that the country would suspend until 2028 talks to join the European Union, a popular national goal for Georgians.

The announcement led to tense daily protests in the capital, Tbilisi, and across the country that often descended into overnight clashes between the protesters and the police.

In another ceremony on Sunday, Georgia’s departing president, Salome Zourabichvili, who over the past months emerged as the leader of the country’s pro-Western movement, said in a speech outside the presidential palace that she would leave office voluntarily. She called Mr. Kavelashvili’s inauguration “a parody” and described the governing party as “scared, illegitimate, sold out, sanctioned and angry.”

“I’m taking away the legitimacy, I’m taking away the flag, I’m taking away what is your trust,” Ms. Zourabichvili told a group of her supporters who had gathered in front of the palace, according to Civil.ge, a local news website.

After the speech, Ms. Zourabichvili joined supporters who then moved to the Parliament building, briefly blocking the city’s main thoroughfare. Six protesters were detained by police officers as they tried to clear the avenue, according to IPN, a local news agency that cited the police as its source for the report.

Georgia’s president occupies a ceremonial post that carries representative duties and functions. But in a country where traditional ceremonies are an integral part of daily life, presidents often assume an outsize symbolic role. While Ms. Zourabichvili was endorsed by the Georgian Dream party in 2018, she gradually began to oppose it. Over the past year she became the most vocal leader of the opposition.

In 2018, the Georgian government changed the way presidents are elected, from a popular vote to an electoral college consisting of members of Parliament and lawmakers from municipal and other assemblies. Mr. Kavelashvili was the first president to be elected under the new procedure.

He was a professional soccer striker for a number of Georgian, Russian and European clubs, including Manchester City in the English Premier League, before beginning his political career in 2016. That year he was elected to the Georgian Parliament as a member of the governing party, Georgian Dream. In 2022, he left the party to found a more anti-Western and People’s Power movement that often criticized the United States as a nefarious power that wants to drag Georgia into Russia’s war with the West.