The United States has welcomed China's restrictions on mineral trade with North Korea, saying it will continue to urge Beijing to do more until there are "concrete signs" of Pyongyang's denuclearization.

This week, China, the North's diplomatic and economic lifeline, imposed restrictions on North Korean coal and iron ore trade, while banning imports of North Korean gold and rare earth, in line with new U.N. sanctions against the North's nuclear and missile programs.

In a statement released on Wednesday, the U.S. Embassy in Beijing said the Chinese measures "appear to be a step toward in following through on" China's pledge in enforcing the U.N. sanctions on North Korea.

"We will continue to urge China to do more until we see concrete signs that Kim Jong-un has come to the realization that the only viable path forward for his country is denuclearization," it said.

The U.N. Security Council adopted a set of new sanctions against North Korea early last month, in the aftermath of the North's fourth nuclear test in January and launch of a long-range rocket in February.

China accounts for nearly 90 percent of North Korea's foreign trade estimated at US$7.6 billion in 2014.

Coal and iron ore are key parts of bilateral trade between North Korea and China, but the U.N. sanctions have an exception that allows trade of such items unless the proceeds are used for the North's nuclear and missile programs.

Chinese officials have pledged to fully implement the U.N. sanctions, but also stressed that it should not affect normal trade between the allies.

In an editorial on Friday, state-run China Daily newspaper said the Chinese restrictions of trade with North Korea "should be a welcome indication that Beijing is serious about its vow to 'conscientiously' implement the sanctions."

Although North Korea has shown no signs of giving up its nuclear ambitions, China has proposed pursuing peace treaty talks with the North in tandem with denuclearization negotiations.

Signing a peace treaty, which would replace the armistice that halted the 1950-53 Korean War, has been one of Pyongyang's long-running goals, but South Korea and the U.S. have demanded the North abandon its nuclear program first.

The Chinese newspaper was also skeptical about the prospects of reviving talks with North Korea.

"So no matter how hard Beijing works to revive talks, it will not happen until Pyongyang convinces the others of its sincerity about denuclearization. Something that appears unlikely at present," the editorial reads.

"Beijing should avoid playing into Pyongyang's hands by single-mindedly advocating for peace. Peace-brokering should never be at the price of appeasing Pyongyang's nuclear ambitions," it said. (Yonhap)