North Korea has said the US used a "mean trick" to obstruct progress at last week's nuclear talks by focusing on Pyongyang's alleged admission that it already had nuclear weapons.
The State Department says North Korea told US negotiators at the talks in Beijing that Pyongyang had nuclear weapons, but North Korea had not publicly commented on this until today.
North Korea said today US policy toward Pyongyang had forced it to develop a "necessary deterrent" and put it into practice.
"The reality requires the DPRK (North Korea) to deter the escalating US moves to stifle the DPRK with physical force, compels it to opt for possessing a necessary deterrent force and put it into practice," said a North Korean Foreign Ministry statement.
The statement said North Korea did not believe the talks had been "ruptured" completely, but that the future of the talks was up to the US.
North Korea's comments follow the US rejection of Pyongyang's offer of giving up its nuclear programme in exchange for economic concessions.
The White House spokesman Mr Ari Fleischer said the US would not "reward North Korea for bad behaviour".
Agencies