SEOUL : US negotiator Christopher Hill left here Saturday for Beijing for talks with officials amid efforts to save a shaky deal on ending North Korea's nuclear weapons programme, the US embassy said.

"I can tell you that at 8:53 this morning, Assistant Secretary (of State) Hill departed for Beijing," embassy spokesman Aaron Tarver told AFP.

Hill arrived in Seoul Friday from Pyongyang where he said he held "very substantive" talks with North Korean officials but gave no further details of his mission to rescue the crumbling six-nation nuclear disarmament pact.

Hill is expected to meet China's chief nuclear negotiator Wu Dawei in Beijing, which hosts the six-nation talks.

Pyongyang accepted the aid-for-disarmament deal struck during six-nation talks in February 2007, just four months after staging its first nuclear test.

It shut down its Yongbyon nuclear complex in July last year and began disabling it in November. And in June it handed over a declaration of nuclear activities to China.

But the North is angry that the United States failed to respond by removing it from a terrorism blacklist, as required under the accord.

The US says the North must first accept strict outside verification of the nuclear inventory that Pyongyang handed over in June, a request it rejects.

The North says it will soon begin work to restart a plutonium reprocessing plant, which could produce more bomb-making material from spent fuel rods.

- AFP/vm