China is temporarily closing its main road connection with North Korea, an official said on Friday.

Foreign ministry spokesperson Geng Shuang said the China-North Korea Friendship Bridge across the Yalu River at the Chinese city of Dandong will be closed while North Korea repairs the approach road on its side.

Geng said that “after the maintenance, the bridge will reopen for passage,” but gave no date for the reopening or other details.

The bridge closure comes after state-owned airline Air China suspended flights on Tuesday between Beijing and North Korea due to a lack of demand, deepening the North's isolation amid mounting UN sanctions.

Beijing is North Korea's only significant ally but has grown increasingly frustrated over its nuclear and missile tests that have brought a threat of war and chaos to China's northeastern border.

In what was seen as a bid to improve relations, the head of the ruling Communist Party's International Department traveled to Pyongyang, North Korea's capital, last week.

Few details have been released about his itinerary, including whether he met with North Korean leader Kim Jong Un.

The trip followed a visit to Beijing earlier this month by US President Donald Trump, who renewed calls for China to step up pressure on North Korea to end its missile and nuclear programs.