FILE PHOTO: An Air China Airbus A330-200 aircraft takes off from Zurich Airport January 9, 2018. REUTERS/Arnd Wiegmann/File Photo

SHANGHAI (Reuters) - State carrier Air China will resume regular flights between Beijing and Pyongyang on Wednesday, a company official said, as diplomatic relations improve between China and North Korea.

China’s flag carrier indefinitely suspended flights between the two cities in November citing poor demand. The suspension came at a time when ties had been frayed by Pyongyang’s nuclear weapons program and Beijing’s backing of tough U.N. sanctions in response.

An Air China company official told Reuters on Tuesday that flights would resume, saying that this was due to “market reasons”. He declined to provide further comment.

The airline now allows travelers to book tickets for the CA121 route from Beijing to Pyongyang which flies on Monday, Wednesday and Friday afternoons, its website showed.

State media has said that Air China flights to Pyongyang began in 2008 but have frequently been canceled because of unspecified problems.

Relations between the two countries have warmed lately with Chinese President Xi Jinping and North Korean leader Kim Jong Un holding two meetings in China since March. North Korea is in the meantime preparing for a summit with U.S. President Donald Trump in Singapore on June 12.

Last month, two officials from North Korea’s Air Koryo told Reuters that the airline planned to launch charter flights between Pyongyang and Chengdu in south-west China amid the diplomatic thaw.