Earlier US Secretary of State Colin Powell said he was encouraged by North Korea's offer Tuesday not to produce or test nuclear weapons and to freeze all nuclear operations.

"We highly value that North Koreans themselves are talking about detailed steps (they need) to take," Yoon said at a press briefing here.

"It is positive in that they reaffirm their willingness to resolve (the nuclear crisis) through dialogue."

North Korea offered on Tuesday to refrain from testing and producing nuclear weapons in what it said was a "bold concession" to the United States.

The Stalinist state said that in return it wanted US aid and an end to US sanctions.

The statement carried by the official Korean Central News Agency was seen here as going further than previous North Korean offers of a nuclear freeze in an effort to jumpstart a new round of six-nation talks to resolve the crisis.

Powell, speaking in Washington, said the offer could speed a resumption of the talks following an acrimonious first round in Beijing in August.

"This is an interesting step on their part, a positive step, and we hope that it will allow us to move more rapidly to six-party framework talks," Powell told reporters on Tuesday.

"I am encouraged, I am encouraged by the statement the North Koreans made."

However, Yoon said that a new round of talks, originally pencilled in for December or January may not take place until mid-year.

"I belive that the six-way talks should resume before the end of June," he said.

The United States has demanded an irrevocable and verifiable decision by North Korea to abandon its quest for nuclear weapons before it will consider offering concession.

On Monday it warned the Stalinist state that it could expect no rewards from Washington for just for showing up at talks, also involving China, Russia, South Korea and Japan.

North Korea's latest offer came as two unofficial US delegations arrived in Pyongyang hoping for a tour of the Yongbyon nuclear complex at the center of a crisis which erupted in October 2002, when Washington accused North Korea of breaching an anti-nuclear pact.

North Korea has made no public comment on the visits which Washington says are private and have no government backing.

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