North Korea has decided to expel UN nuclear inspectors as it moves towards reactivating its nuclear programme, the country's official news agency has declared.

A letter to the International Atomic Energy Agency (IAEA) - the UN's nuclear watchdog - also said Pyongyang was planning to reopen a reprocessing plant, which could start producing weapons grade plutonium within months.

CRISIS CHRONOLOGY

16 Oct: N Korea acknowledges secret nuclear programme, US announces 14 Nov: Fuel shipments to N Korea halted 12 Dec: N Korea threatens to reactivate Yongbyon N-plant 22 Dec: N Korea removes monitoring devices at Yongbyon reactor 26 Dec: UN says 1,000 fuel rods have been moved to the plant 27 Dec: N Korea says it will expel UN nuclear inspectors

Timeline of tensions

In his response, IAEA Director General Mohamed ElBaradei said North Korea should let the inspectors stay.

A 1994 fuel aid deal which had led to the closure of the Yongbyon plant broke down last month when the US suspended shipments - alleging that the North had admitted to restarting a nuclear weapons programme.

Observers say Pyongyang's move may be aimed at forcing the United States to sign a non-aggression pact with the North.

But a White House spokeswoman repeated on Friday that Washington would not negotiate in response to "threats or broken commitments".

Claire Buchan said North Korea should scrap its nuclear weapons programme.

"We call on the DPRK to reverse its current course and to take all steps necessary to comply with the IAEA ... to eliminate its nuclear weapons program in a verifiable manner."

Inspectors staying

The IAEA chief said the presence of inspectors was needed for "the immediate installation of containment and surveillance measures".

"This is one further step away from defusing the crisis," Mr ElBaradei said.

He said he expected the North Korean Government to inform him immediately, "so that, if necessary, arrangements for the departure of IAEA inspectors can be made".

Until the response is received, the IAEA inspectors will stay in the country.

"They are on standby," the IAEA spokeswoman Melissa Fleming said.

Pyongyang has already removed IAEA-installed equipment and seals from Yongbyon - what the agency calls its "eyes and ears" at the plant - in preparation for reactivation.

According to Pyongyang, the location would be used to give "safe storage" to spent fuel rods that will come from the controversial Yongbyon nuclear plant being reactivated.

"Together with the loss of cameras and seals [on equipment], the departure of inspectors would practically bring to an end our ability to monitor DPRK's nuclear programme or assess its nature," Mr ElBaradei said.

Looming 'confrontation'

It remains unclear exactly what Pyongyang wants, but observers suggest it may be looking to force the US into signing a non-aggression pact and to secure further aid.

The BBC's Charles Scanlon says North Korea is moving rapidly towards provoking a full-scale confrontation over its nuclear programme.

Earlier on Friday, Pyongyang warned that the US was heading for an "extremely dangerous confrontation", after Washington said it would not enter into dialogue "in response to threats".

This is one further step away from defusing the crisis Mohamed ElBaradei IAEA Director General

Click here for full text of North Korea letter

International concern has been mounting over the prospect of conflict between North Korea and the US since US Defence Secretary Donald Rumsfeld declared earlier this week that war against Iraq would not stop military action elsewhere.

Japan has joined the calls from international community urging Pyongyang to scrap its nuclear arms programme.

Japanese Foreign Minister Yoriko Kawaguchi said there were "grave concerns" about nuclear non-proliferation.

And earlier South Korea's President-elect Roh Moo-hyun also weighed into the debate for the first time on Friday.

He warned that Pyongyang's moves to reactivate the Yongbyon reactor could severely hamper efforts to rebuild ties between the two countries.

UN experts have said the reactor could be operational within two months.

NORTH KOREA NUCLEAR PROGRAMME

Yongbyon: Five-megawatt experimental nuclear power reactor and partially completed plutonium extraction facility. Activities at site frozen under 1994 Agreed Framework Taechon: 200-MWt nuclear power reactor - construction halted under Agreed Framework Pyongyang: Laboratory-scale "hot cells" that may have been used to extract small quantities of plutonium Kumho: Two 1,000-MWt light water reactors being built under Agreed Framework

Analysis: North Korea's nuclear progress

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