SEOUL, South Korea - Hours after announcing its intention to withdraw from the Nuclear Nonproliferation Treaty, North Korea issued a mixture of threats and calls for negotiations yesterday, warning that any attempt by the United Nations Security Council to impose sanctions would be a "declaration of war."

It again blamed the United States for tensions over the regime's nuclear program while also seeking formal negotiations with the United States, apparently as the surest route to increase its own prestige and win aid from Washington.

In New York, North Korea's ambassador to the United Nations, Pak Gil Yon, criticized the Bush administration's offer to hold talks as insincere, even as informal talks in Santa Fe, N.M., were about to resume. Yet he also suggested that "any problem could be resolved pacifically" - by negotiation with the United States.

The United States condemned North Korea's decision to withdraw from the nonproliferation treaty and said it increased the possibility that North Korea could build up to a half-dozen nuclear weapons within the next several months.

President Bush conferred by telephone with President Jiang Zemin of China, the country that is traditionally North Korea's strongest ally. The White House said the two leaders agreed that North Korea's latest actions were "a concern to the entire international community."

"The president stressed that the United States has no hostile intentions toward North Korea, and sought a peaceful, multilateral solution to the problem created by Pyongyang's action," White House spokesman Ari Fleischer said.

The State Department said that North Korea's assertion that it was withdrawing from the nonproliferation treaty effective as of today was improper because the treaty requires 90 days' notice for such action.

By claiming that its withdrawal was taking effect today, Pyongyang apparently hoped to place itself beyond the reach of treaty provisions that would allow the Security Council to apply sanctions.

Talks in New Mexico

Pak blamed the United States for his country's actions. "It is none other than the United States which [wrecks] peace and security on the Korean Peninsula," he said reading from a prepared statement, "and drives the situation there to an extremely dangerous place."

Gov. Bill Richardson of New Mexico, a former U.S. ambassador to the United Nations, meanwhile held a second day of talks in Sante Fe with two North Korean diplomats who traveled there Thursday from New York.

Secretary of State Colin L. Powell said the administration "will not enter any kind of talk or dialogue where North Korea is given any impression but that they have to come into compliance" with the nonproliferation treaty. "This kind of disrespect for this kind of agreement cannot go undealt with."

Here as well as in Washington, analysts assumed that North Korea's latest actions were less a signal that it was about to develop nuclear weapons than an effort by a regime desperately short of food and electricity to win concessions from the one country it believes can enhance Pyongyang's standing - the United States.

North Korea's actions are "designed to draw attention and to make North Korea's situation a priority for the Bush administration and the international community," said Scott Snyder of the Asia Foundation, a U.S. government-supported think tank in Seoul.

"Their negotiating style is widely associated with brinkmanship at this point, and one reason is that it is a tactic which on specific issues, where the conditions are right, it can help to level the playing field between a weak state and a strong state - and the nuclear issue happens to be one where those conditions are right," Snyder said.

Closer to arms program

In recent months North Korea appeared to move closer to launching a nuclear weapons program. North Korean officials admitted the existence of a secret uranium enrichment program, dismantled U.N. monitoring cameras, expelled U.N. inspectors and declared their intention to resume reprocessing plutonium, which could make the material available for use in weapons.

At every turn, the regime blamed the United States for the tensions and demanded one-on-one negotiations for American security guarantees. Bush administration officials insisted that negotiations could not begin until the North canceled nuclear programs that could lead to the production of nuclear weapons.

Pak said that his country's nuclear activities would be limited "at this moment purely for the peaceful purposes, such as generation of electricity. But the future developments will entirely depend on the attitude of the United States."

North Korea has been careful to direct its ire at the United States and not South Korea, in hopes of driving a wedge between the two. The North characterizes America as an aggressor seeking to invade the North, and has said it is willing to deal only with the United States on the nuclear issue.

The situation closely follows the path charted almost a decade ago, the last time North Korea announced intentions to withdraw from the nonproliferation treaty.

North Korea agreed, in 1994, to abandon its nuclear weapons program in exchange for the United States and its allies providing shipments of fuel oil as well as two reactors for the production of electricity. But last month North Korea declared that agreement dead and announced its intention to restart its Yongbyon nuclear reactor.

In announcing its intention to withdraw from the nonproliferation treaty, the North characterized the United Nations International Atomic Energy Agency as "a tool" of the United States.

For all the concern in Washington and the United Nations, North Korea's actions have yet to concern the young people of South Korea, who live within artillery range of the North.

"In a way that's kind of funny because maybe it's people like me who should be getting nervous about it rather than people in the U.S.," said Park Gunn Ho, 29, a graphics designer whose father is a retired Korean diplomat. "But that's how I feel about North Korea's actions right now. It doesn't bother me that much."

"I really don't think they want to start a war, and they're just using the nuclear treaty and the threat of the nuclear bomb itself to get in a better position to negotiate with the U.S.," he said. "They just want to keep their regime intact and start economic growth, and I guess the only economic leverage they have right now is their weapons industry."

China as U.S. ally

An American diplomat in Seoul said that more of North Korea's neighbors are potential allies of the United States now than during the last nuclear crisis with the North, in 1994. At the top of that list is China, which the diplomat described as North Korea's "life support" in terms of aid.

China's Foreign Ministry expressed "concern" yesterday at the North's announcement of withdrawal from the treaty, but it has shown no inclination to support economic sanctions against the North.