A senior North Korean envoy said today that the country was unable to meet its obligations under a key non-proliferation pact because of nuclear threats by Washington, Interfax news agency said.
Mr Pak Ui Chun, Pyongyang's ambassador to Moscow, was quoted as saying the United States had followed moves to cut off fuel oil supplies by "threatening us with a preventative nuclear strike".
"In these circumstances, we also cannot fulfill the Non-Proliferation Treaty, the basic clause of which is the obligation of nuclear states not to use the nuclear weapon against states which do not possess it," he said.
The secretive Stalinist state joined the treaty, designed to stop the spread of nuclear weapons and technology, in December 1985.
It said on Friday it was re-activating a reprocessing laboratory that could convert spent fuel into the plutonium needed for making nuclear bombs and had begun moving fresh fuel rods to a five-megawatt research reactor.
It ordered International Atomic Energy Agency (IAEA) monitors to leave the country, escalating a crisis that analysts say is part of a bid to secure aid from Washington and its allies.
North Korea said it was taking this action because a 1994 agreement had broken down. Under the pact, the United States, the European Union, Japan and South Korea promised North Korea oil and nuclear power stations for civilian use in return for a freeze on a plutonium-based nuclear arms programme.
The North Korean ambassador blamed Washington for the crisis, saying the United States "openly tries to internationalise the nuclear question on the Korean peninsula by creating an atmosphere of pressure on the Democratic People's Republic (North Korea)".
Repeating Pyongyang's calls for direct negotiations with the United States, he said the Korean nuclear question was not an international issue and could be solved only by Pyongyang and Washington.
The United States has labelled North Korea part of an "axis of evil", along with Iran and Iraq, for seeking weapons of mass destruction.
Russia, whose relations with North Korea have warmed under President Vladimir Putin, yesterday denounced Pyongyang's nuclear moves but also told Washington to halt "aggressive rhetoric" towards Pyongyang.