The U.N. nuclear agency declared North Korea in violation of international treaties Wednesday, raising the stakes in the standoff by sending the dispute to the Security Council.

The move could lead to punishing sanctions which the North has said it would consider an act of war.

Russia and Cuba refused to endorse the measure, saying the International Atomic Energy Agency's decision would detract from a flurry of diplomatic efforts aimed at easing the crisis.

Agency chief Mohamed ElBaradei said the IAEA would continue to press for a peaceful solution, but he said months of intransigence on the part of North Korea's communist regime had left the U.N. nuclear watchdog no choice.

"The current situation sets a dangerous precedent," ElBaradei said. He said North Korea was only a "month or two" from producing "a significant amount of plutonium" that could be diverted for making weapons, now that IAEA inspectors no longer controlled the country's nuclear programs.

U.S. intelligence officials, meanwhile, warned that Pyongyang has an untested ballistic missile capable of hitting the western United States. The North Korean missile is a three-stage version of the Taepo Dong 2, said Vice Adm. Lowell Jacoby, director of the Defense Intelligence Agency.

Although North Korea has held to a voluntary moratorium on flight tests of its long-range missiles, U.S. officials fear Pyongyang likely will conduct new tests.

White House spokesman Ari Fleischer praised the IAEA action, calling it a "clear indication that the international community will not accept North Korea's nuclear program." He said the conflict pits North Korea against the world, not just the United States.

"This is a matter to be settled through diplomacy," Fleischer said.

In its resolution that sent the standoff to the Security Council, the IAEA's 35-nation board of governors said North Korea had not met its obligations under the Nuclear Nonproliferation Treaty and other accords.

Because the North has expelled U.N. inspectors, the agency "remains unable to verify that there has been no diversion of nuclear material" for weapons use, it said.

Because of the North's belligerent threats of war, it was unclear whether the Security Council would impose sanctions, especially in light of objections from Russia and China, permanent council members with veto power.

ElBaradei suggested the Security Council for now would stop short of punishing the already impoverished country with sanctions.

"The message is ... let us first try a diplomatic solution as we are trying in Iraq," he said. "But if it doesn't work, I haven't heard any member say that the Security Council is not considering other options."

Abstaining from the vote, Russia's representative called the IAEA move "premature and counterproductive." Cuba also sat out the vote, saying there were still "diplomatic options to exhaust."

South Korea, the most vulnerable to any nuclear weapons the North might be trying to produce, said Pyongyang's actions "seriously endanger the peace and stability on the Korean peninsula and in the whole East Asian region."

But Seoul, which has taken the lead in efforts to negotiate an end to the crisis, said reporting the North to the council did not mean diplomacy would end.

That was ElBaradei's message as well. "The agency of course is not washing its hands of the matter," he told reporters. "This does not close doors to a diplomatic solution."

The crisis began in October, when U.S. officials said North Korea admitted having a nuclear weapons program in violation of a 1994 agreement.

The United States and its allies suspended oil shipments to the impoverished communist country. North Korea in turn expelled IAEA inspectors, disabled the agency's monitoring cameras, withdrew from a global nuclear arms-control treaty and said it would reactivate its main nuclear complex, frozen since 1994.

Japan urged the North on Wednesday to respond "immediately and positively" to the IAEA's demands for compliance.

The standoff comes at a particularly trying time for the nuclear agency, whose inspectors have been in Iraq since late November searching for evidence of atomic weaponry. ElBaradei, however, has taken what he calls a "zero tolerance" approach toward what he termed North Korea's "nuclear brinkmanship."

Despite a flurry of diplomatic efforts to ease the crisis, a rift widened Tuesday when China dismissed a request from Washington that it become more involved in the standoff.

The North accuses the United States, which maintains 37,000 troops in South Korea, of using concerns over nuclear weaponry as a pretext to invade.