Top nuclear envoys from South Korea and the US held talks yesterday on a strategy to bring North Korea back to disarmament negotiations, a day after the North claimed to have succeeded in experimental uranium enrichment.

US special envoy on North Korea Stephen Bosworth and South Korean envoy Wi Sung-lac made no comment after their meeting. Bosworth later met with South Korea's unification minister in charge of relations with North Korea. Bosworth said in Beijing this weekend that any nuclear development in North Korea was a matter of concern.

"We confirm the necessity to maintain a co-ordinated position and the need for a complete denuclearisation of the Korean peninsula," he said.

North Korea's claim that it is in the final stages of enriching uranium raises the possibility that it might do that to its stockpile of bombs made from plutonium. Uranium offers an easier way to make nuclear weapons. North Korea also said it is continuing to weaponise plutonium.

Washington shows no signs of easing pressure on North Korea through sanctions, although the North has also recently made conciliatory gestures, including the release of two American journalists and a reported invitation to top US envoys, including Bosworth, to visit.