Seoul, South Korea ? North Korea triggered global alarm on Tuesday by saying it will conduct a nuclear test, a key step in the manufacture of atomic bombs that it views as a deterrent against any U.S. attack. But the North also said it was committed to nuclear disarmament, suggesting a willingness to negotiate.

The contradictory statement fits a North Korean pattern of ratcheting up tension on the Korean Peninsula, a Cold War-era flashpoint, in an attempt to win concessions such as economic aid. The strategy has had mixed results in recent years as the totalitarian regime sinks deeper into isolation and poverty, with China serving as its lifeline for food and fuel.

Secretary of State Condoleezza Rice called the announcement “a very provocative act” and urged Asian nations to rethink their relationships with North Korea.

The North’s announcement came as the standoff deepened over Iran’s nuclear program, with senior U.N. diplomats saying six world powers would begin negotiations Friday in London on possibly imposing sanctions against Tehran for refusing to suspend uranium enrichment.

It was the first time the North had publicly announced its intent to conduct a nuclear test. Previously, it had warned that it might conduct a test, depending on U.S. actions.

“The U.S. extreme threat of a nuclear war and sanctions and pressure compel the DPRK to conduct a nuclear test, an essential process for bolstering nuclear deterrent, as a self-defense measure in response,” said a statement by the North’s Foreign Ministry and carried by the North’s official Korean Central News Agency. DPRK stands for Democratic People’s Republic of Korea, the North’s official name.

Yet it said it wanted to “settle hostile relations” between the North and the United States, and that it “will do its utmost to realize the denuclearization of the peninsula.”

Many North Korea watchers believe the country’s dictator, Kim Jong Il, knows that all-out confrontation with the United States would lead to his destruction. Even if Kim seeks negotiations, though, the risk of a miscalculation that spirals out of control cannot be ruled out.

The North Korean statement did not say when a nuclear test might occur, but the prospect drew rebukes from Japan, South Korea and the United States. The allies, along with China and Russia, had participated in the stalled six-party talks aimed at getting the North to give up its nuclear ambitions.

The announcement was not a big surprise to many observers of North Korea because U.S. intelligence reports had indicated that Pyongyang might be preparing a nuclear test. Many experts believe the North has enough radioactive material to build at least a half-dozen or more nuclear weapons.

“They are an active proliferator,” said Defense Secretary Donald H. Rumsfeld. “And were they to test and were they then to proliferate those technologies, we’d be living with a proliferator and obviously we’d be living in a somewhat different world.”

During a visit to Egypt, Rice said the United States would have to assess its options if the North carries out the test, without detailing what those options were. She stressed, however, that a North Korean test was an issue “for the neighborhood” and not just for the United States.

“It would be a very provocative act,” Rice said. “A North Korean nuclear test : would create a qualitatively different situation on the Korean peninsula,” Rice said. “I think that you would see that a number of states in the region would need to reassess where they are now with North Korea.”

The remarks appeared directed primarily at China and South Korea.