The United States on Sunday kept up its demand for China to use its "unique leverage" on North Korea to pressure the regime in Pyongyang after Beijing suspended coal imports from the neighboring nation.

China's Commerce Ministry announced Saturday it is suspending North Korean coal imports starting Sunday through the end of the year in accordance with the latest UN Security Council resolution adopted in December to punish Pyongyang for its fifth nuclear test in September.

The resolution centers on putting a significant cap on North Korea's exports of coal -- the country's single biggest export item and source of hard currency. The cap was set at whichever is lower between 7.5 million tons or $400 million.

"All countries should fully and transparently implement all relevant UN Security Council Resolutions on the DPRK. We continue to urge China to exert its unique leverage as North Korea's largest trading partner to convince Pyongyang to return to serious talks on denuclearization," a State Department spokesperson told Yonhap News Agency.

The official made no mention of praising or welcoming the Chinese decision.

On Friday, Secretary of State Rex Tillerson made the same demand when he met with Chinese Foreign Minister Wang Yi for the first time as secretary, urging China to "use all available tools to moderate North Korea's destabilizing behavior."

Their meeting took place in the Germany city of Bonn on the sidelines of a meeting of the foreign ministers of the Group of 20 nations.

China is North Korea's last-remaining major ally and a key provider of food and fuel supplies. But it has been reluctant to use its influence over Pyongyang for fears that pushing the regime too hard could result in instability in the North and hurt Chinese national interests.

Beijing often increased pressure on the North in the past, especially when Pyongyang defied international appeals and carried out nuclear and missile tests and other provocative acts, but it never went as far as to cause real pain to the North. (Yonhap)