One of Air China's Airbus A330-300s has suffered serious damage during a fire at Beijing Capital airport.

Air China says passenger boarding had been under way for the aircraft, which was due to operate the CA183 service to Tokyo Haneda.

It says that, during the boarding process, the cargo area at the front of the aircraft "smoked" and the crew "quickly executed firefighting measures" and evacuated the passengers.

"The specific cause of the incident is under investigation," says the carrier.

Images from the scene circulating on social media show thick smoke billowing from the twinjet, and indicate that the crown of the fuselage has suffered substantial damage.

The airport's operator states that there were no passengers on the aircraft as the emergency developed, and that the incident resulted in smoke from the cargo hold.

It adds that the accident occurred at about 16:00.

Preliminary indications from the social media footage suggest the aircraft involved is B-5958, a 2014 airframe powered by Rolls-Royce Trent 700 engines, which had previously arrived from Singapore.