Obama earlier this week pledged to resist using nuclear weapons against nations that comply with nonproliferation standards - exempting North Korea and Iran from the new policy. Miffed by Obama's words, North Korea accused his government of being no better than the Bush administration, "hell-bent on posing a nuclear threat" to North Korea.

"As long as the US nuclear threat persists, (North Korea) will increase and update various type nuclear weapons as its deterrent in such a manner as it deems necessary in the days ahead," the official Korean Central News Agency quoted an unidentified Foreign Ministry spokesman as saying Friday.

Washington and other regional powers have been trying to coax North Korea back to disarmament talks it walked out of last year, but the ministry was quoted as saying Obama's new policy "chilled the hard-won atmosphere for the resumption of the talks." Still, US Secretary of State Hillary Rodham Clinton said Friday she is confident the disarmament talks will resume, despite instability in the North that she says has hindered negotiators.

Clinton said in a speech in Louisville, Kentucky, that the North will be pushed back to the talks because negotiators from the other participants - the US, China, South Korea, Japan and Russia - are unified.

North Korea cites a US threat as a main reason behind its drive to build nuclear weapons. The US has 28,500 troops in South Korea to guard against the North. The two Koreas remain locked in an official state of war because their three-year conflict ended in a truce, not a peace treaty, in 1953.