President Bush (searchconferred with the leader of South Korea on Monday and claimed progress was being made "on peacefully solving" a crisis with North Korea by offering Pyongyang (searchwritten security assurances in exchange for a commitment to scrap its nuclear weapons program.

Bush and South Korean President Roh Moo-hyun (searchmet over breakfast a day after Bush rejected North Korea's demand for a formal no-invasion treaty, but left the door open for some form of written security pledge backed by the United States, China, Japan, South Korea and Russia.

Nuclear tensions hung over the opening of a 21-nation summit of Asian-Pacific leaders, along with disputes over trade and the U.S. occupation of postwar Iraq. On the economic front, China refused to give ground in a currency argument with Washington.

In his talks with Roh, Bush said, "We have a common goal to make sure that the Korean Peninsula is nuclear weapons free."

While administration officials said Bush's initiative was still in the early discussion stage with allies, the president said, "We're making good progress on peacefully solving the issue with North Korea." He said he would talk with Roh about how to move the process forward.

Roh, speaking through a translator, said he appreciated Bush's efforts and said, "this issue is very critical."

Bush, who acknowledged to a reporter that he was feeling a bit jet-lagged from his Asian travel, also said he would talk with Roh about trade issues and U.S. demands that trade be "free and fair."

National Security Adviser Condoleezza Rice (searchtold reporters that consultations are just beginning -- that no draft had yet been circulated.

"The key here is that anything having to do with security guarantees obviously also has to do with performance by the North Koreans," she said. "And it has to do with North Koreans being willing, able and verifiably capable of carrying out the obligations that they undertake."

"We want to discuss this with our partners. We are not going to go in all guns blazing and say `Take it of leave it this is it.' But, one thing should be very clear, this have to be performance-based. What will not work."

North Korea also was at the top of the agenda Sunday when Bush met with Chinese President Hu Jintao, who pledged to encourage North Korea to return to multiparty nuclear talks soon.

With at least two nuclear weapons in its arsenal, North Korea startled the world last year when it admitted running a secret weapons program. In August, talks between the United States, China, Russia, Japan and the two Koreas in Beijing ended without agreement on a next round.

The administration fervently wants to avoid Bush having a nuclear crisis on his hands as he heads into a re-election battle next year.

Russian President Vladimir Putin said more nuclear talks could yield "good, positive results" if North Korea's security worries were addressed. Japanese Prime Minister Junichiro Koizumi backed the push for new negotiations.

"I've said as plainly as I can say that we have no intention of invading North Korea," Bush said after a meeting with Thai Prime Minister Thaksin Shinawatra. "And I've also said as plainly as I can that we expect North Korea to get rid of her nuclear weapons ambitions."

But, he said, short of a treaty, "perhaps there are other ways to say exactly what I said publicly" and to put it on paper "with our partners' consent."

At a photo session with Hu, the Chinese president said only that he would "strive for a peaceful resolution."

North Korea said the meeting in Bangkok was not the place to discuss the nuclear standoff because it "is an issue to be resolved between us and the United States."

On the sidelines of the economic summit, Bush talked with Mexico President Vicente Fox about the North America Free Trade Agreement, immigration and Bush thanked him for his help in the recent U.N. resolution on Iraq, Rice said.

Meanwhile, Bush made little apparent progress in his drive to persuade China to stop a policy that keeps its currency undervalued compared to the U.S. dollar, making Chinese goods less expensive than American products.

Neither Bush nor Hu directly mentioned the dispute before reporters. However, Hu said, "We both stated our readiness to resolve whatever questions that might emerge in our economic exchange through dialogue."

Privately, Hu told Bush he agreed that market forces should determine exchange rates, but that to do so too quickly would shock to China's economy, said a senior Bush official. The official said Hu agreed to set up an "experts group" to study ways China could move more quickly.

But before meeting with Bush, Hu defended the currency policy, telling international business executives that China's rapid ascendance as a major trading nation was benefiting the world.

With financial commitments from Japan and South Korea in hand, Bush said he would use the annual Asia-Pacific Economic Cooperation forum here to encourage more nations to be contribute to Iraq's reconstruction. The U.S.-led attack against Iraq was opposed by many nations here, including Russia and Muslim countries.

Canadian Prime Minister Jean Chretien requested a formal one-on-one meeting with Bush, but so far, his request has been met by U.S. silence. The relationship, which has never warmed between the two leaders, further soured when the prime minister refused to send Canadian troops to Iraq earlier this year.