At the airport’s arrivals hall, an agonizing wait for news.

Officials were investigating what caused the tragedy, including why the plane’s landing gear appeared to have malfunctioned, whether birds had struck the jet, or if bad weather had been a factor.

The airport in Muan had warned the plane’s pilots about a potential bird strike as they were landing, said Ju Jong-wan, a director of aviation policy at the Ministry of Land, Infrastructure and Transport. The plane issued a mayday alert shortly afterward, then crash-landed, he added, saying later that the plane’s black boxes — which should help determine the cause of the crash — have been recovered.

Jeju Air flight 7C2216 had 175 passengers and six crew members on board. Hundreds of people — grandparents, parents and children — packed the Muan airport waiting anxiously for news about their loved ones.

As of Sunday evening, the government said, 179 people had been confirmed dead. As investigators worked to identify the bodies, officials posted lists in the airport of the names that had been confirmed and collected DNA from relatives.

More than 1,500 people were deployed to help search the wreckage; at least two crew members were rescued from the aircraft’s tail section.

Lee Jeong-hyeon, an official in charge of search and rescue operations at the scene, said the plane had broken into so many pieces that only its tail was identifiable.

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

Here’s what else to know about the crash:

• Photos from the South Korean news agency Yonhap showed a tail section of the plane separated and engulfed in orange flames with black smoke billowing up. The plane appears to have hit a concrete wall, according to the photos.

• The disaster was the worst involving a South Korean airline since 1997 when a Korean Air jet slammed into a hill in Guam, a U.S. territory in the western Pacific. That crash killed 229 of the 254 people on board.

• Jeju Air apologized for the crash in a brief statement. The crash on Sunday appears to have been the first fatal one for the airline, a low-cost South Korean carrier that was established in 2005 and flies to dozens of countries in Asia.

• Thailand’s Foreign Ministry confirmed that there were two Thai passengers on the plane. It said it was trying to verify their conditions.

• South Korea has been dealing with a political crisis at the highest levels. President Yoon Suk Yeol, who was impeached this month after a short-lived martial law decree shocked and angered the nation, wrote on social media on Sunday that he was devastated by the accident. South Korea’s acting president, Choi Sang-mok, said the country would observe a weeklong period of mourning.

Yan Zhuang and Sui-Lee Wee contributed reporting.

Jang Gu-ho, 68, sat stoically in the arrivals hall beside his teary-eyed wife after rushing to the airport 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. His wife was too overcome with emotion to speak.

As the death toll from the crash climbed, in a restricted area of the airport, officials were working to identify the bodies that had been recovered from the scene. In the arrivals hall, fire, police and transport officials periodically announced updates on their progress to the waiting families.

By around 4:30 p.m., the officials told the crowd that they had confirmed the identities of 22 people. As an official named each victim, people began to cry. Others raised their voices in frustration: “Speak up!” “Print out the names!” “How many hours has it been?”

The officials said that they were working as quickly as they could to identify the victims. By about 5 p.m., printed lists of the confirmed names were posted on the wall of the arrivals hall. People rushed to check the lists for their family members.

The first 22 names were all Korean nationals who had been identified by their fingerprints, according to the lists. They ranged from a 23-year-old flight attendant to a 78-year-old male passenger. Fire officials later said they had identified 65 of 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.

Mr. Jang and his wife had been at the airport since about half past noon after getting a call from a nearby town hall’s office saying that it had been notified of a passenger on the plane who was related to him.

Six hours after the couple dashed to the airport, there were still no answers.

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

An official at Muan airport is announcing the names of those who have been confirmed dead. Some of the people who have been waiting anxiously at the airport for news of their loved ones are crowding around the official to double-check whether their relative is on the list. Officials have also been collecting DNA samples from relatives at the airport to help identify the bodies recovered from the crash site.

All 22 are Korean nationals who have been identified by their fingerprints, according to the lists. They range from a 23-year-old flight attendant to a 78-year-old male passenger.

Nearly 200 airlines use the 737-800, according to Cirium, including five in South Korea: Jeju Air, T’way Air, Jin air, Eastar Jet and Korean Air. The plane is popular in Asia, Europe and North America, and Boeing has delivered about 5,000 to customers since 1998.

“The plane in question is very safe and has a good safety record,” said Najmedin Meshkati, a professor of engineering at the University of Southern California who has studied the safety history of the Boeing 737 line.

The age of the global fleet of 737-800 planes ranges from about 5 years old to more than 27 years old. A well-maintained passenger jet can fly 20 to 30 years or even longer. According to the flight tracking website Flightradar24, the plane that crashed was 15 years old. Ryanair in Europe was the first airline to operate the aircraft, which was leased to Jeju Air in 2017 by SMBC Aviation Capital, according to Cirium.

Officials said they were investigating the cause of the crash, including the possibility that a bird strike led to a landing gear malfunction.

Boeing said in a statement on Sunday that it was in contact with Jeju Air and was ready to help the airline.

Bird strikes are not uncommon in aviation. In some cases, they have resulted in cracked windshields. Some airports deploy falcons and take other measures to keep their skies clear of birds. Muan International Airport, where the crash occurred, uses measures such as playing audio of distress calls to disperse birds as well as shooting them, according to the Korean Office of Civil Aviation.

Mr. Meshkati said that the landing gear of the 737-800 line is well designed and has a history of reliability, though poor upkeep could result in it not deploying correctly. “Maintenance is really one of the most important causes of aviation accidents,” he said.

But Mr. Meshkati and other aviation experts cautioned against rushing to judgment about such incidents. Crashes are often caused by multiple factors, which can take years to uncover through in-depth investigations.

The officials said that they were working as quickly as they could to identify the victims, including with fingerprints.

Diversions can happen for a range of reasons, including medical emergencies, harsh weather, low fuel or mechanical problems.

The diversion two days ago was caused by a medical, not technical, emergency on board, according to the Incheon International Airport Police Corps.

The runways at Incheon International Airport in Seoul range from 3,700 to 4,000 meters, or around 12,100 to 13,100 feet.

“We lower our heads in apology to everyone who suffered in the accident,” Jeju Air said in a brief statement posted on its website. “We will do everything we can to deal with this accident.”

The plane involved in the crash had been flying to Beijing from Jeju, a Korean island south of the mainland, two days ago, but had to divert to Seoul, according to the flight tracking site Flightradar24. The diversion was caused by a medical, not technical, emergency on board, according to the Incheon International Airport Police Corps.

After that, the plane flew 10 flights between South Korea, Malaysia, Japan, China, Taiwan and Thailand without incident, according to Flightradar24, before Sunday morning’s crash.

Last year, the airline received a safety grade of A, or “very good,” from the South Korean Ministry of Land, Infrastructure and Transport’s annual review of domestic airlines. The score is based on the number of accidents or near accidents. The highest grade any airline got that year was A++, and the lowest was B+.

In 2021, the South Korean authorities investigated Jeju Air after one of its planes flew despite having a defect, according to reports in the domestic news media. The plane had damaged the tip of a wing during landing, but the crew failed to notice the damage, and the plane took off again, the Korea Herald reported. That year, the airline got a C for safety.

It was unlikely that the crash was related to broader aviation safety issues in South Korea, said Keith Tonkin, the managing director of Aviation Projects, an aviation consulting company in Brisbane, Australia. “South Korea’s safety record is very good.”

Mr. Choi, who arrived at the site about 190 miles from Seoul around midday Sunday, ordered government agencies to mobilize all equipment and personnel available for rescue efforts, according to his office.

The leadership crisis started when President Yoon Suk Yeol made an ill-fated declaration of martial law earlier this month, setting off protests and the most serious constitutional crisis in the country since it democratized in the late 1980s.

Mr. Yoon was impeached by lawmakers on Dec. 14 over the martial law bid, leaving South Korea without an elected leader. At first, the prime minister, Han Duck-soo, served as acting president, but he, too, was impeached by lawmakers, on Friday, less than two weeks into his term.

That was when Mr. Choi, the deputy prime minister and finance minister, was named acting president. Like Mr. Han, Mr. Choi has no electoral mandate.

Mr. Choi had been a career bureaucrat, climbing the ranks at the finance ministry. He served as a deputy finance minister when former President Park Geun-hye was impeached and removed from office in 2017. He then left government until Mr. Yoon picked him as his presidential secretary for economic affairs in 2022 and later made him the finance minister.

The second major impeachment in two weeks meant that South Korea continued to be without a strong elected leader in charge of the government and military in one of Washington’s most important allies, at a time when the country is grappling with North Korea’s nuclear threats and economic challenges at home.

The political uncertainty has pushed business and consumer confidence lower and caused the currency, the won, to plunge.

A new government cannot be formed until the Constitutional Court decides whether to reinstate or formally oust Mr. Yoon. The court can take up to six months to reach its decision.