SEOUL, South Korea -- Brightening prospects for ending a nuclear stalemate, North Korea said Saturday it will consider President Bush's offer of written security assurances in return for dismantling its nuclear weapons program.

It was the latest about-face by North Korea, which had called the offer "laughable" and "not worth considering" and has been unclear about its actions and plans during the yearlong dispute over its atomic ambitions.

Still, the abrupt shift raised hope of resuming six-nation talks aimed at ending the standoff. U.S. officials believe Pyongyang already has one or two atomic bombs and can yield several more bombs within months from its nuclear programs.

North Korea has already informed the Bush administration of its new intentions through its diplomats at the United Nations, said an unnamed spokesman for Pyongyang's Foreign Ministry.

The White House responded to North Korea's latest comment with guarded optimism.

"We're looking at the message, and we hope North Korea will return to the Beijing six-party talks," said Jimmy Orr, a spokesman for President Bush.

Separately, the Japanese government said North Korea may have test-fired a short-range missile off its eastern coast Saturday. It is the third suspected missile launch by Pyongyang this week.

A U.S. official said on condition of anonymity that the North Koreans normally do such testing in three stages, and this one appeared to have been previously scheduled.

"We are ready to consider Bush's remarks on the 'written assurances of nonaggression' if they are based on the intention to coexist with the North" and offer "simultaneous actions," the North Korean spokesman said.

The comments were carried by Pyongyang's official KCNA news agency.

North Korea has previously said that "simultaneous actions" include economic and humanitarian aid from the United States, opening diplomatic ties, and building a nuclear power plant. It has also said it must include a nonaggression treaty -- something the Bush administration has refused.

In exchange, North Korea has said it would declare its willingness to give up nuclear development, allow nuclear inspections, give up missiles exports and finally dismantle its nuclear weapons facilities.

The North Korean spokesman said it was "premature" to talk about whether his country would return to six-nation talks. Pyongyang must first confirm that the United States will take "simultaneous actions" toward ending the nuclear crisis, he said.

"Simple and clear is our request," the North Korean spokesman said. "What we want is for both sides to drop guns and establish normal state relationship to coexist peacefully."

North Korea was now "in the process of ascertaining the real intention of the U.S.," he said.

U.S. officials pledged to maintain their New York contact with North Koreans, he added.

South Korea welcomed the North's comments.

"This is a positive development ahead of future six-party talks," said Ban Ki-moon, President Roh Moo-hyun's adviser on diplomatic affairs, according to South Korea's Yonhap news agency.

Representatives of the United States, China, Russia, Japan and South and North Korea met in Beijing in August for their first round of six-nation talks aimed at ending the North Korean nuclear crisis. But the meeting ended without agreement on a new round, as the United States and North Korea failed to narrow their differences.

Washington demanded that North Korea first shut down its nuclear program immediately while Pyongyang said it would do so only after the United States signed a formal nonaggression treaty and granted economic aid.

In recent weeks, North Korea added urgency to the crisis by declaring that it is using plutonium extracted from its 8,000 spent nuclear fuel rods to build new atomic bombs, besides the one or two it is already believed to possess. Last week, it threatened to test a bomb.

Bush made his overture amid international efforts to bring North Korea back to the negotiating table. Wu Bangguo, head of China's legislature and the Communist Party's No. 2 man, will travel to Pyongyang next week to encourage North Korea to return to the talks.

The nuclear dispute flared last October, when U.S. officials said North Korea admitted having a secret nuclear weapons program in violation of international agreements.