CRISIS CHRONOLOGY

16 Oct: N Korea acknowledges secret nuclear programme, US says 14 Nov: Oil shipments to N Korea halted 22 Dec: N Korea removes monitoring devices at Yongbyon nuclear plant 26 Dec: UN says 1,000 fuel rods have been moved to the plant 31 Dec: UN nuclear inspectors leave North Korea 6 Jan: IAEA demands inspectors be readmitted and secret weapons programme halted 7 Jan: US "willing to talk" to North Korea 10 Jan: N Korea pulls out of nuclear treaty 11 Jan: Pyongyang suggests it could resume ballistic missile tests

Timeline of tensions

Pak Ui-chun also told Russian reporters that North Korea "was ready to prove" it was not developing clandestine nuclear weapons at the Yongbyon plant, which experts say can be used to produce plutonium.

But Mr Pak said progress could only be made if the United States gave up what he called its "hostile" policy towards Pyongyang.

On Tuesday, Pyongyang will receive a senior Australian delegation - the first mission by a Western state since the nuclear crisis started to develop in October.

Although contacts are expected to remain at the vice-ministerial level, the visiting diplomats are hoping to present Foreign Minister Paek Nam-sun with a letter from his Australian counterpart, Alexander Downer.

It reportedly urges his co-operation with diplomatic moves to lower tensions in the region.

Nuclear 'necessity'

The Interfax news agency quoted Ambassador Pak as saying the question of rejoining the Nuclear Non-Proliferation Treaty (NPT) - which it withdrew from last week - "will be decided depending on the situation".

If the United States renounces its hostile policies and nuclear threats against North Korea, then we do not exclude the possibility of proving... that we are not producing nuclear weapons Pak Ui-chun, North Korean ambassador in Moscow

He added that North Korea "does not intend to produce nuclear weapons, and the nuclear programme is limited to civilian use".

He also suggested that independent monitors might be allowed to scrutinise its operations. Pyongyang expelled UN monitors in December.

North Korea maintains it has no choice but to restart its nuclear plants to produce electricity, as the US halted fuel shipments in October.

Washington stopped the aid after alleging that North Korea had admitted to resuming a nuclear programme.

On Monday, US envoy James Kelly said the US could resume fuel shipments to North Korea, if there was a nuclear solution.

First move

Mr Kelly suggested that "once we get beyond nuclear weapons, there may be opportunities with the US, with private investors, with other countries to help North Korea in the energy area". He was speaking after holding talks with South Korean leaders in Seoul.

Mr Kelly also reiterated Washington's willingness to hold talks with North Korea, and hinted at energy aid.

Mr Pak, however, insisted that the US would have to make the first move.

North Korea has witnessed rallies showing mass support for its leader

"If the United States renounces its hostile policies and nuclear threats against North Korea, then we do not exclude the possibility of proving - through separate checks conducted between the United States and North Korea - that we are not producing nuclear weapons," he was quoted as saying.

Observers have suggested that North Korea has been hoping all along to force the US into signing a non-aggression pact and stumping up fresh aid by pushing the nuclear issue.