A bridge providing the main road link between China and North Korea is to be closed "temporarily" while workers on the North side carry out maintenance, Beijing announced Friday.

Some 70 percent of trade between the Asian neighbours is conducted in the northeastern Chinese city of Dandong, connected to North Korea by the Sino-Korean Friendship Bridge.

"The bridge will be closed temporarily because the DPRK (North Korean) side needs to carry out some repair and maintenance work," Chinese foreign ministry spokesman Geng Shuang told reporters at a regular news briefing on Friday.

The closure would take place within "days," Geng said, without specifying any timeframe for the work to be completed and the bridge re-opened.

China is North Korea's largest trading partner, but it has backed a series of United Nations sanctions against Pyongyang over its nuclear and missile activities, straining ties between the Cold War-era allies.

US President Donald Trump has urged his Chinese counterpart Xi Jinping to use his economic leverage to exert more pressure on the pariah state in the hopes it might abandon its nuclear weapons programme.

However, Beijing this week condemned as "wrong" fresh US sanctions that targeted North Korean shipping interests as well as Chinese companies that do business with the North. (AFP)