BANGKOK, Thailand -- President Bush conferred with the leader of South Korea and said "we're making good progress on peacefully solving" a crisis with North Korea by offering Pyongyang written security assurances in exchange for a commitment to scrap its nuclear weapons program.

Bush and South Korean President Roh Moo-hyun met over breakfast Monday, Sunday night Cape Girardeau time, 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 pledged 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 also said he would talk with Roh about trade issues and U.S. demands that trade be "free and fair."

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.

'No intention of invading'

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, while South Korea had no comment on the day's developments.

"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."

But administration leaders, following Bush's lead, made themselves available on Sunday talk shows to discuss the new proposed approach, described by one official as an "agreement with a small 'a."'

"We believe that we could provide the kind of assurances that the North Koreans say they are looking for, without getting it into the formal process of a treaty ... that will require Senate ratification," Secretary of State Colin Powell said on CBS' "Face the Nation."

He made clear the United States wants to first gain agreement from key regional allies before it would go to Pyongyang. "I would not want to prejudge right now what other parties might be willing to do," Powell said on "Fox News Sunday."

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."

Economic shock worries

Privately, Hu told Bush he agreed that market forces should determine exchange rates, but that to do so too quickly would shock 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 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.