A passenger plane has caught fire before takeoff at an airport in South Korea, but all 176 people on board have been safely evacuated.

South Korean officials are launching an investigation into the cause of the fire that engulfed an Air Busan passenger plane, with eyewitness accounts suggesting a power bank may have sparked the blaze.

An Airbus plane belonging to South Korean carrier Air Busan caught fire on Tuesday at Gimhae International Airport in the country’s south while preparing for departure to Hong Kong, fire authorities said.

Shares of Air Busan dropped on Friday, after a plane belonging to the budget carrier caught fire earlier this week. Air Busan shares traded down 3.8% as of 0018 GMT, after falling as much as 6.1% to 2,

The first report on last month’s Jeju Air crash in South Korea has confirmed traces of bird strikes in the plane’s engines, though officials haven’t determined the cause of the accident that killed all but two of the 181 people on board.

An investigation into a fire that engulfed an Air Busan plane at a South Korean airport this week is being slowed by a large amount of fuel and oxygen still on board, an air crash investigation official told Reuters.

Passengers evacuated from an Air Busan plane that was engulfed in flames this week at a South Korean airport will have their checked baggage returned to them, after authorities on Friday deemed the jet safe for a full investigation.