South Korean officials are launching an investigation into the cause of the fire that engulfed an Air Busan passenger plane while awaiting takeoff at Busan's Gimhae International Airport, with some eyewitness accounts leading to speculation that a portable power bank may have caused the blaze.

Shares of Air Busan dropped on Friday, after a plane belonging to the budget carrier caught fire earlier this week.

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.