US envoy Joseph DeTrani conveyed the message to China's pointman on North Korea Ning Fukui in talks here described as "in-depth" by Beijing.

"In these meetings, DeTrani is conveying the well-known US position which includes the necessity for any resolution to the North Korean nuclear problem to address all North Korean nuclear programs," said an embassy spokesman.

China is North Korea's closest ally and host of six-party negotiations to resolve the issue. It has called for Washington and Pyongyang to show more mutual trust.

According to US Assistant Secretary of State James Kelly, Washington's chief negotiator at the six-party talks, North Korea acknowledged at the last round in June that most of its nuclear programs were weapons related.

At that third round of talks in Beijing, Pyongyang proposed freezing its nuclear weapons programs for rewards, including energy aid, the lifting of sanctions and North Korea's removal from the list of nations sponsoring terrorism.

But the United States has said the proposal lacked detail and was vague.

Of particular concern was that it ignored the Stalinist state's pre-2003 plutonium nuclear weapons and its alleged uranium enrichment program.

The United States, for its part, made an offer calling for a step-by-step dismantling of Pyongyang's plutonium and uranium weapons programs in return for aid and security guarantees and the easing of its political and economic isolation.

The embassy said DeTrani continued his meetings Friday on preparations for a next round of six-party working group sessions which would precede a fourth round of full-blown talks.

After meeting the US envoy, Chinese Vice Foreign Minister Wang Yi called for the talks to be reconvened as soon as possible so they could work on how to "implement the first stage of nuclear abandonment".

"All concerned parties should hold the working meeting ... as soon as possible in line with the consensus reached in the third round of six-party talks," Wang was quoted as saying by Xinhua news agency.

The US embassy said DeTrani was "flexible" on dates.

Japanese media has reported that the working level talks would take place in August, although there has been no confirmation of this.

Aside from the United States and North Korea, the other parties at the talks are host China as well as Russia, South Korea and Japan.

The standoff erupted in October 2002 when the United States accused Pyongyang of operating a nuclear weapons program based on enriched uranium, violating the 1994 nuclear freeze of its separate plutonium producing program.

Pyongyang has denied running the uranium-based program, but has again fired up its once-mothballed plutonium-based program.

US intelligence authorities say North Korea is believed to possess at least one or two nuclear bombs.

WAR.WIRE