China, South Korea, Japan and Russia are also involved in the negotiations aimed at persuading Pyongyang to back down from its nuclear ambitions in exchange for energy and food aid.

The working-group meetings -- the second round at this level -- are scheduled to run until Tuesday with the full blown talks starting Wednesday and expected to conclude on Saturday.

The American working group, headed by former CIA officer Joseph DeTrani, had talks Sunday, according to the US embassy, although it was unclear with whom.

Expectations of concrete results from the six-party talks are low, with the US apparently sticking to its hardline stance of a "complete, verifiable and irreversible dismantlement" of North Korea's nuclear programs, both plutonium and enriched uranium.

The impasse blew up in October 2002 when Washington said the Stalinist state had broken a 1994 nuclear freeze by launching a secret nuclear weapons program.

Pyongyang denies that it is running a uranium scheme, but has offered to freeze its plutonium facilities in return for simultaneous rewards from the United States.

Chinese foreign ministry spokesperson Zhang Qiyue last week called for only a "reasonable expectation" for the third round vice-ministerial level talks, noting that as the negotiations deepened, differences and difficulties increased.

WAR.WIRE