N Korea must stop its nuke plan: Rice

Rice also appealed to China, communist North Korea's closest ally, to use its leverage to bring North Korea back to disarmament talks.

"We are committed to diplomacy, but I think it goes without saying that no one is going to be prepared to allow the North Koreans to just go down a road that threatens everyone," Rice said.

"We have been very careful to have people choose their own diplomatic paths and their own mix of incentives and leverage to deal with the North Korean problem," she said.

Rice spoke from Tokyo before flying to South Korea.

The North Koreans have not responded to a US-backed peacemaking proposal. Pyongyang has complained that Rice unfairly labelled the country an "outpost of tyranny" earlier this year, and demanded an apology.

North Korea has said it wants nuclear weapons as a defence against a potential attack from US and South Korean forces. President Bush has said the United States has no intention of attacking North Korea.

Meanwhile, the US Secretary of State visited yesterday the highly secretive command post for US-South Korea joint forces as the two allies kicked off an annual military exercise.

Having arrived at a military airbase in southern Seoul, she took a helicopter to fly to a nearby underground bunker used as the command post for the ongoing US-South Korea joint military exercises.

North Korea has used the week-long drill, which it also says is aimed at making a pre-emptive strike against the communist state, to justify the bolstering of its "self-defensive nuclear arsenal."