Updated

In the face of defiance and threats from its neighbor to the north, South Korean officials went to work this weekend on a compromise proposal designed to peacefully draw North Korea away from its nuclear program.

South Korean Vice Foreign Minister Kim Hang-kyung arrived at Moscow's International Airport Saturday and told reporters he's counting on help from Russia, one of the north's few allies, in diffusing the increasingly tense situation.

And in what will likely be a crucial meeting, South Korea's national security adviser, Yim Sung-joon, is scheduled to visit Washington from Tuesday to Thursday to meet with his counterpart, Condoleezza Rice, other White House officials, and representatives from Japan. The South Korean proposal is expected to dominate a joint strategy session.

Japan's Kyodo News agency reported that Japan has already agreed with the United States to use diplomatic pressure in resolving the issue. Japanese Foreign Minister Yoriko Kawaguchi and Secretary of State Colin Powell concurred on the approach during telephone talks late Saturday, Kyodo said.

In advance of that regular session to review policy toward the North, the Bush Administration had not budged from its demand that the communist regime in the North unilaterally abandon its nuclear ambitions before Washington considers a next step.

Details of the Seoul plan were scant, but media reports suggested the proposal would require concessions from both Washington and Pyongyang. The Korea Herald, an English-language paper, reported that South Korea may ask Washington to back off its current line and guarantee North Korea's security in exchange for giving up its nuclear ambitions.

Russian President Vladimir Putin has moved to reinvigorate Moscow's strong Soviet-era ties with North Korea, hosting its reclusive leader Kim Jong Il for the second consecutive summer last year. Moscow has said it wants to link its trans-Siberian railroad with a railway being rebuilt between North and South Korea.

Seoul's diplomatic offensive underlines its new drive to mediate between the United States, its key ally, and neighboring North Korea, its erstwhile enemy. But brokering a deal won't be easy.

The United States refuses to talk until the North scraps its nuclear programs. And North Korea insists Washington must take the first step by signing a nonaggression pact promising not to attack the isolated country.

"There is no reason why the U.S. should not accept the proposal, the best way for peaceful solution," the North's state-run news agency KCNA said. "The present situation is very serious and unpredictable."

Still, officials in Seoul were upbeat about a diplomatic solution.

"We are getting closer to finding an answer," a senior government official said on condition of anonymity after Saturday's security meeting.

In past crises with the North, Seoul played a subordinate role to the United States. Now many South Koreans want their government to help chart the course of talks and assume more equal footing with Washington.

Being heard out by the United States is also seen as soothing rocky relations with South Korea amid rising public resentment over 37,000 U.S. troops based here.

The trilateral meeting — Monday and Tuesday in Washington — is part of the allies' regular forum for coordinating policy toward the communist North. This time, they will focus on bringing North Korea's nuclear weapons programs under international controls.

The communist North alarmed the world in October by admitting to a U.S. envoy it had a secret uranium-based nuclear weapons program, in violation of a 1994 accord.

As punishment, the United States and its allies halted oil supplies promised in the agreement. North Korea then announced it would reactivate its older plutonium-based nuclear program, saying it needs to restart a reactor to generate electricity.

The United States says the plutonium-based program, at the Yongbyon complex north of Pyongyang, could be used to build nuclear weapons. And Washington has indicated North Korea may already have two nuclear weapons and can build several more in short order.

One South Korean compromise being considered calls for the United States to resume oil shipments to North Korea, in return for it abandoning its uranium nuclear development, media reported Saturday, citing an unnamed government source.

President-elect Roh Moo-hyun intends to unveil his compromise plan in hopes the crisis can be defused before he takes office Feb. 25.

Giving the North oil removes any justification for its restarting a nuclear complex to produce electricity, the reports said. A government spokesman could not immediately comment.

State Department spokesman Richard Boucher indicated Friday that Washington would not compromise. "We have no intention of sitting down and bargaining again," he said.

In Beijing, the North's ambassador to China described the situation as "getting worse and worse," but indicated Pyongyang would welcome a mediator.

Moscow and Beijing, two of North Korea's traditional allies, want a nuclear-free Korean Peninsula. But so far, they have stopped short of declaring that they will aggressively pressure the North to give up its weapons programs.

The North and South have remained divided since the end of the 1950-53 Korea War, which ended not in a peace treaty but an armistice.

The Associated Press contributed to this report.