South Korea's acting President Choi Sang-mok on Monday ordered an emergency safety inspection of the country's entire airline operation system as investigators worked to identify victims and find out what caused the country's deadliest air disaster.

All 175 passengers and four of the six crew were killed when a Jeju Air (089590.KS), opens new tab Boeing (BA.N), opens new tab 737-800 belly-landed and skidded off the end of the runway at Muan International Airport, erupting in a fireball as it slammed into a wall. Two crew members were pulled out alive.

The top priority for now is identifying the victims, supporting their families and treating the two survivors, Choi told a disaster management meeting in Seoul.

"Even before the final results are out, we ask that officials transparently disclose the accident investigation process and promptly inform the bereaved families," he said.

"As soon as the accident recovery is conducted, the transport ministry is requested to conduct an emergency safety inspection of the entire aircraft operation system to prevent recurrence of aircraft accidents," he said.

The transport ministry said authorities were considering whether to conduct a special inspection of all 101 Boeing 737-800 aircraft operated by South Korean airliners.

Jeju Air flight 7C2216, arriving from the Thai capital Bangkok, was trying to land shortly after 9 a.m. (0000 GMT) on Sunday at the airport in the south of the country.

Investigators are examining bird strikes and weather conditions as possible factors in the crash, fire officials have said.

Experts say many questions remain, including why the plane, powered by two CFM 56-7B26 engines, appeared to be travelling so fast and why its landing gear did not appear to be down when it skidded down the runway and into a wall.

CFM International is a joint venture between GE Aerospace (GE.N), opens new tab and France's Safran (SAF.PA), opens new tab.

On Monday, transport ministry officials said as the pilots made a scheduled approach they told air traffic control the aircraft had suffered a bird strike, shortly after the control tower gave them a warning birds were spotted in the vicinity.

The pilots then issued a mayday warning and signalled their intention to abandon their landing and to go around and try again. Shortly afterwards, the aircraft came down on the runway in a belly landing, touching down about 1,200 metres (1,312 yards) along the 2,800 metres (3,062 yard) runway and sliding into a structure at the end of the runway.

Officials are investigating what role the localiser antenna, located at the end of the runway to help in landing, played in the crash, including the embankment on which it was standing, transport ministry officials told a media briefing.

"Normally, on an airport with a runway at the end, you don't have a wall," said Christian Beckert, a flight safety expert and Lufthansa pilot based in Munich. "You more have maybe an engineered material arresting system, which lets the airplane sink into the ground a little bit and brakes (it)."