FILE PHOTO - Flights of Air China are parked on the tarmac of Beijing Capital International Airport in Beijing Thomson Reuters TAIPEI/BEIJING — Air China has indefinitely suspended flights between Beijing and Pyongyang, citing poor demand as North Korea faces growing sanctions from the United States over its nuclear weapons and missile programs.

An official in the company's Beijing-based press office, who gave only his surname as Ding, told Reuters on Wednesday that flights were suspended because "business was not good." He declined to comment on when flights might resume.

The suspension by China's national flag carrier comes shortly after a visit by a senior Chinese envoy to the city and coincides with a US decision to put North Korea back on a list of state sponsors of terrorism.

Air China flights to Pyongyang — which have traditionally operated on Monday, Wednesday, and Friday — began in 2008 but have frequently been canceled because of unspecified problems, state media has said.

Last year, Air China halted flights seasonally for winter but resumed them in March. So far it is not selling tickets for any 2018 flights, according to Routes Online.

One staff member in the company's Pyongyang office who declined to give his name told Reuters that Air China could resume the flights when there was enough demand, adding that the office would operate even while there were no scheduled flights between Beijing and Pyongyang.

Air China's Beijing-based press office declined to comment further.

The company canceled some flights in April but later said it would increase their number in May.

The United States has urged China to do more to press North Korea to stop what the United States sees as belligerent defiance of UN resolutions.

China's foreign ministry on Tuesday said it hoped all parties could contribute to resolving the issue on the Korean Peninsula peacefully. It also said it was not aware of the Air China situation, adding that airlines made their decisions based on market needs.

(Reporting by Brenda Goh in Taipei and Se Young Lee in Beijing; additional reporting by Ben Blanchard in Beijing, Jamie Freed in Singapore and Shanghai Newsroom; editing by Richard Pullin)