Seoul: US envoy James Kelly on October 19 said that the United States wanted a peaceful solution to the North Korean nuclear crisis, but warned Pyongyang to "immediately" drop its nuclear weapons programme.

Kelly said that the United States would continue to work with South Korea, Japan and other allies to prompt an "immediate and visible dismantling" of North Korea's nuclear programme.

"We hope to bring maximum international pressure (on North Korea) to abandon its nuclear ambition," he told reporters.

Two weeks ago Kelly, the US assistant secretary of state for East Asian and Pacific affairs, made the first high-level US contact with the regime in nearly two years when he travelled to Pyongyang to confront North Korea with evidence that it was running a nuclear programme.

He said that the North had been engaged in an enriched uranium nuclear programme for years and the United States had yet to determine the next step if the Stalinist regime pushed ahead with it.

"There is no deadline to this. This is a difficult and complex problem," he said. "We're just going to have to see how it unfolds," he added.

Kelly was speaking after meeting with top advisors to President Kim Dae-Jung and South Korean Foreign Minister Choi Sung-Hong following his arrival here from Beijing, where he held two rounds of talks on the nuclear crisis with Chinese officials.

Kelly's talks are part of a US drive to step up international pressure following the North's bombshell admission that it has been pursuing a nuclear weapons programme.

The United States on October 16 revealed the startling admission made to Kelly on his visit to Pyongyang a fortnight ago.