BEIJING (AP) — An airliner operated by North Korea's flag carrier caught fire and made an emergency landing in northeastern China on Friday, an airport police official said.

The Air Koryo flight was en route from the North Korean capital of Pyongyang to Beijing when it made the unscheduled stop in the Chinese city of Shenyang, the Xinhua News Agency said, citing a passenger on board the plane.

An official with the Shenyang Taoyuan Airport police unit, reached by phone, said the plane landed at around 9 a.m. local time. Like many Chinese officials, he refused to provide his name and said he had no further details.

Air Koryo operates mainly Russian TU-204 and AN-148 planes. The international destinations to which it flies regularly include Beijing, Shanghai and Shenyang in China and the Russian port of Vladivostok.

Calls to the airline's office in Beijing rang unanswered.

Xinhua cited the unidentified passenger as saying that smoke began to appear in the cabin around half an hour after the plane took off from Pyongyang. The report said the crew told passengers the plane would make a stop in Shenyang and urged them not to panic. It said oxygen masks were released and the plane made a forced landing in Shenyang 10 minutes later.

Xinhua cited Chinese ground staff as saying the plane had caught fire. Its report did not mention what might have caused the fire and gave no word on any injuries or damage to the plane.