The Chinese government said it was also against Washington's call for imposing UN sanctions on North Korea a day after Pyongyang raised the stakes by announcing it had taken another step towards making nuclear weapons.

"In principle the Chinese government is not in favor of exerting pressure. We do not support resorting to sanctions to resolve international conflicts," foreign ministry spokesman Kong Quan told a regular briefing.

"Facts have proven that pressure will not help solve the question but further complicate the situation," he said.

The United States on Wednesday called on China to use its leverage to help persuade the North Koreans to return to negotiations that collapsed last June after three sessions.

"We do think that robust diplomacy is necessary in this case, if North Korea has resisted entreaties to come back to the talks, but exactly how to do that, I think we'll leave to the Chinese," State Department spokesman Richard Boucher said.

But China on Thursday argued it was up to the Americans and North Koreans to create the right atmosphere for talks.

"The most important thing at present is for North Korea and the United States, the two major parties concerned, to do more positive things and send more positive signals," the spokesman said.

This could help facilitate the early resumption of talks or at least create a favorable for six-party talks, he added.

Beijing has hosted the three rounds of talks also involving the two Koreas, the United States, Japan and Russia aimed at solving the standoff over North Korea's nuclear ambitions.

A fourth round, originally scheduled for September last year, has so far not taken place due Pyongyang's reluctance to return to the negotiating table.

Little progress has been recorded in efforts to end the nuclear standoff since it erupted in October 2002. Pyongyang declared in February that it was already nuclear-armed.