North Korea does not plan to rejoin the Nuclear Nonproliferation Treaty but would agree to let the United States verify that it is not producing nuclear weapons if Washington drops its hostile stance, the country's U.N. ambassador said Friday.

Hours after the North Korean government announced its withdrawal from the 1968 global treaty that barred it from making nuclear weapons, Ambassador Pak Gil Yon held a rare news conference to say the country will not develop nuclear weapons "at this moment."

He would not comment on whether North Korea already possesses one or two nuclear weapons and stressed that "future developments will entirely depend on the attitude of the United States."

Pak said North Korea plans to reactivate a nuclear reactor in the town of Yongbyon and complete construction of two other reactors, which will meet the country's energy and electricity demands "in the very near future." Activity at all three sites was frozen under a 1994 energy deal with the United States which Pyongyang has abandoned.

North Korea blamed "the U.S. vicious hostile policy" and an alleged "nuclear threat from the United States side" for its decision to pull out of the treaty, which has been ratified by 188 countries and is considered the cornerstone of international efforts to prevent the spread of nuclear weapons.

Pak restated North Korea's desire to resolve the nuclear issue through "peaceful negotiations" between Pyongyang and Washington, and said it wants a nonaggression treaty with the United States. He said the U.S. decision to talk -- but not negotiate -- "is not a sincere attitude."

Pak made clear that his government wants no more dealings with the Vienna-based International Atomic Energy Agency, which monitors adherence to the treaty. He accused the agency of being "a tool" to implement hostile U.S. policies.

But he said the North was willing to work directly with the United States. A statement issued by the government in Pyongyang held out the possibility of a future North Korea-U.S. agreement on nuclear verification.

"If the United States drops its hostile policy and stops its nuclear threat to the DPRK, the DPRK may prove through a separate verification between the DPRK and the U.S. that it does not make any nuclear weapons," the statement said, referring to the North's full name, the Democratic Peoples Republic of Korea.

Whether such an arrangement would be acceptable to the United States was not immediately known.

When asked under what conditions North Korea would return to the treaty, known by its initials NPT, the ambassador replied: "We never say (there is) any possibility of returning to the NPT. My government decided to withdraw from the NPT, effectively from tomorrow, immediately."

Diplomats said Pak's language did not completely close the door on rejoining the treaty.

U.S. Ambassador John Negroponte condemned the North Korean decision.

"We reject North Korea's claims that actions by the United States and the International Atomic Energy Agency justify its actions," he said. President Bush and U.S. Secretary of State Colin Powell "have indicated repeatedly that the United States has no hostile intent," he said.

Negroponte called on North Korea to reverse its decision and reiterated that Washington seeks a peaceful solution. U.N. Secretary-General Kofi Annan also urged North Korea to reconsider.

Pak forwarded a letter to the Security Council from North Korean Foreign Minister Paek Nam Sun enclosing the government's statement explaining its decision.

The letter noted that the government initially decided to withdraw from the treaty on March 12, 1993, and had suspended its decision on June 11, 1993, one day before the 90-day notification period ended. Paek said North Korea was now revoking the suspension, and its withdrawal would be effective as of Saturday.

France's U.N. Ambassador Jean-Marc de la Sabliere, the current council president, said members would discuss the letter next week.

Last week, the IAEA's governing body gave North Korea another chance to abandon its covert weapons program and readmit inspectors, but warned of confrontation if it failed to comply. The next step would likely be referring the issue to the Security Council, which could impose diplomatic and economic sanctions.