A portable power bank likely caused a fire that engulfed and destroyed a passenger plane in South Korea in January, according to local authorities.

The Air Busan plane caught fire at Gimhae International Airport in the country’s south on 28 January – causing three people on board to sustain minor injuries.

On Friday, South Korea’s transport ministry said that interim investigation results indicate the fire may have started because insulation inside a power bank battery had broken down.

The power bank was found in an overhead luggage compartment where the fire was first detected, and its debris had scorch marks, according to the statement.

Investigators could not say what may have caused the battery breakdown, it added.

The update is also based only on interim findings, and is not a final accident report on the aircraft, an Airbus A321ceo.

Airlines around the world have banned power banks from checked luggage for years due to safety concerns, which relate to the lithium-ion batteries inside the devices.

These batteries can produce extreme heat and fire if damage or manufacturing faults cause them to short circuit.

Lithium-ion batteries of any kind have been banned from the cargo holds of passenger planes since 2016, as per a directive by the International Civil Aviation Organisation.

In the week after the Air Busan fire, the airline tightened those rules further, announcing that it would no longer allow passengers to keep power banks in their onboard luggage.

The carrier said the new rules were in response to an increase in the number of power banks that were overheating.

A growing number of airlines – including China Airlines and Thai Airways – are rolling out similar rules, with Singapore Airlines and its low-cost unit Scoot set to become the latest to ban the use and charging of power banks onboard from 1 April.

On 28 February, the South Korean government also announced that passengers boarding flights in the country would be required to carry portable batteries and chargers on their person, rather than storing them in overhead compartments.