A passenger’s portable charger burst into flames on a China Eastern Airlines’ flight on Wednesday morning, forcing the aircraft to make an emergency landing, according to the carrier.

The incident occurred on flight MU2809, which had departed Nanjing in neighboring Jiangsu Province for Xiamen in southeast Fujian Province, SHINE reported.

According to a witness onboard, a passenger’s charging unit caught fire around 8 am, shortly after the aircraft reached cruising altitude. Cabin crew members responded quickly to extinguish the flames and contain safety risks.

The incident prompted the flight’s captain to return to Nanjing Lukou International Airport, according to a statement from the Shanghai-based carrier.

The carrier later dispatched another aircraft to take the passengers to Xiamen. The flight landed at around 1:30 pm.

Police are currently investigating the matter. No injuries were reported.

Domestic airlines have been urged to enhance security checks following similar incidents involving portable chargers, the report said.

In a previous incident, fire broke out in an overhead compartment inside a China Southern Airlines aircraft in February 2018 before it took off from Guangzhou to Shanghai. The blaze was sparked by a portable charger in a passenger’s bag. No one was injured.

Under current rules of the Civil Aviation Administration of China, portable chargers are not allowed in check-in luggage and each passenger can carry up to two portable chargers with capacity of no more than 160wh, or 43,000mAh at 3.7V.

The administration further stipulates that chargers must not be used while aircraft are in flight.

Passengers should be advised not to carry portable chargers on board, while crew members should undergo special training in how to put out fires which result from overheating chargers, the administration said.

“Portable chargers are likely to overheat and even ignite when being used,” said a senior captain with Longhao Aviation Group, a cargo airline.

“However, there are still a lot of passengers who use chargers in the air,” he said. In the incident on Wednesday, if the charger was being used, the owners could face fines or other punishments, he added.

According to Chinese law, people who violate the rules of public transportation including buses, boats, trains and airplanes can face up to 10 days in detention, plus a fine.