MUAN, South Korea — Flags flew at half-mast on Monday as South Korea mourned 179 people killed in the worst plane crash on its soil, as investigators probe why the Jeju Air plane crash-landed and burst into flames.

The country has announced seven days of national mourning, with the acting president flying to the crash site in southwestern Muan for a memorial as teams of US and South Korean investigators raced to establish what caused Sunday's disaster.

The Boeing 737-800 was carrying 181 people from Thailand to South Korea when it made a mayday call and belly-landing before crashing into a barrier and bursting into flames. Everyone on board Jeju Air Flight 2216 was killed, save two flight attendants pulled from the wreckage.

Officials initially cited a bird strike as a likely cause of the crash, which flung passengers from the plane and left it "almost completely destroyed", according to fire officials.

Seoul said on Monday it would conduct a special inspection of all 101 Boeing 737-800s in operation in the country, with US investigators, possibly including those from beleaguered plane manufacturer Boeing, joining the probe into the crash.

"We are reviewing plans to conduct a special inspection on B737-800 aircraft," said Joo Jong-wan, head of the aviation policy bureau at South Korea's transport ministry.

Transportation ministry officials said the jet's flight data recorder was recovered but appeared to have sustained some damage on the outside and it was not yet clear whether the data was sufficiently intact to be analyzed.

South Korean investigators said on Monday that 141 of the 179 victims had now been identified using DNA analysis or fingerprint collection, according to a statement from South Korea's Ministry of Land.

At the crash site early on Monday, a middle-aged man and woman kept their gaze fixed through the fence, where remnants of the plane, seats, gates, and twisted metal parts were still scattered across the field near the charred tail.

South Korea's acting president, Choi Sang-mok, who has only been in office since Friday, said the government was making "every effort" to identify victims and support bereaved families.

Choi said on Monday a "thorough investigation into the cause of the accident" would be conducted.

He also said South Korea would conduct "an urgent safety inspection of the overall aircraft operation system" to prevent future aviation disasters.

Carrier Jeju Air said it "sincerely" apologized, with top officials shown bowing deeply at a news conference in Seoul. Shares of Jeju Air hit their lowest level on record on Monday, trading as much as 15.7 percent lower.

The Muan airport will remain closed through Wednesday but the rest of the country's international and regional airports, including the main Incheon International Airport, were operating as scheduled.

As the nation mourns for the victims, some questioned if the crash involved safety or regulatory issues.

The crash was yet more big news for South Koreans as they reel from a political crisis set off by impeached President Yoon Suk-yeol's martial law decree. The safety minister stepped down and the police chief was arrested over their roles in the martial law enhancement.

Concerns voiced

The absence of top officials responsible for managing disasters has also led to concerns.

"We are deeply worried if the Central Disaster and Safety Countermeasures Headquarters really can handle the disaster," the mass-circulation JoongAng Ilbo newspaper said in an editorial on Monday.

A growing chorus of criticism from experts analyzing dramatic video footage of Flight 2216's landing has focused on whether airport construction could have played a part.

Kim Kwang-il, a professor of aeronautical science at Silla University in Busan and a former pilot, said he was "quite upset" when he reviewed the video showing the plane making a skilled emergency landing but then hitting a wall.

"There shouldn't have been a solid structure in that area at all," he told AFP.

"Normally, at the end of a runway, there's no such solid obstruction, it's against international aviation safety standards," he said.

Meanwhile, another Jeju Air flight experienced a malfunction linked to the landing gear and was forced to return to Seoul's Gimpo Airport shortly after takeoff, the Yonhap News Agency reported on Monday.

The Boeing 737-800 involved in the latest incident was the same model as the Jeju Air plane that crashed on Sunday.

2024 was already a dispiriting year for Boeing, the US aviation giant. The problem marked another setback for Boeing.

For decades, Boeing has maintained a role as one of the giants of US manufacturing. But the past year's repeated troubles have been damaging. The company's stock price has fallen more than 30 percent in 2024.

Agencies Via Xinhua