State-owned airline Air China has suspended flights between Beijing and North Korea due to a lack of demand, deepening the North's isolation amid mounting UN sanctions over its nuclear and missile programmes.
The move followed US president Donald Trump's decision to add Pyongyang to a list of governments that support terrorism, but there was no indication that prompted Air China's decision.
The suspension left North Korea's Air Koryo as the only airline with regularly scheduled service to the North. Its website lists flights to Beijing, Shanghai, Shenyang and Dandong in China, and Vladivostok in Russia.
Beijing has supported UN curbs on North Korean exports meant to pressure the government of leader Kim Jong Un to drop its pursuit of nuclear and missile technology, but has argued against measures that might harm the country's public.
Flights were "temporarily suspended due to unsatisfactory business operations," said an Air China employee.
A foreign ministry spokesman, Lu Kang, said he had not heard about Air China's cancellation. He said such decisions would be made based on the "state of operation and the market".
Airlines have steadily reduced the frequency of flights to North Korea as mounting political tensions depressed the already small number of business travellers and tourists visiting the North.
Air China Ltd announced in April it was cutting the frequency of flights to North Korea due to lack of demand. Some other Chinese carriers offered charter services to the North but those have also been cancelled.
Mr Lu appealed for measures to ease the tense stand-off over the North.
He said: "Given the highly complex and sensitive situation on the peninsula, we hope all relevant parties can do something conducive to alleviating the tension and pulling all sides concerned back to the track of negotiation and dialogue to settle the peninsular nuclear issue."