North Korea has threatened never to return to the six-party nuclear talks if US officials continue criticizing its leadership.

A North Korean foreign ministry spokesman on Thursday said that despite the high priority of the six-party talks, recent comments by US Vice President Dick Cheney are just short of telling Pyongyang not to return to the talks,

In a CNN interview Monday, Cheney called North Korean dictator Kim Jong-il one of the world’s most irresponsible leaders.

The spokesman said Washington has recently reaffirmed the North's sovereignty and its intention not to invade, but high-level US officials continue pressuring the North with disparaging remarks about its leader.

Stressing the sovereign North has never yielded to outside pressure, he said it is preposterous for Washington to argue with Pyongyang on nuclear weapons since US pressure forced the North to develop them in the first place.