South Korea won a promise from Russia on Sunday to press North Korea over its nuclear program, as Seoul prepared to unveil to the United States new proposals aimed at defusing the crisis with its communist neighbor.
As the South launched a diplomatic blitz, the North opened the door to possible mediation -- though it said it would heighten its combat readiness and denounced the United States.
In Moscow -- one of the isolated North's few allies -- South Korean Deputy Foreign Minister Kim Hang-kyung met with his Russian counterpart, Alexander Losyukov.
Losyukov said after the talks that Moscow and Seoul "agreed to make joint efforts to ease the crisis" and persuade the parties to sit down for talks, though he stopped short of promising Russian mediation.
"The slide to unacceptable actions must be stopped," Losyukov was quoted as saying by the Russian news agency Interfax. "Obviously, our contacts with North Korean colleagues will be intensified."
A separate team of South Korean diplomats also was expected to present a compromise solution to the United States and Japan on Monday and Tuesday, when the three allies meet in Washington to chart a joint strategy on North Korea. Seoul said it will send a top presidential envoy to the United States for more talks later this week.
No details have been disclosed on the South's proposals, but it is expected to involve North Korean concessions on nuclear weapons in exchange for security guarantees.
The current standoff began when North Korea announced last month that it was reviving its main nuclear complex, frozen since a 1994 deal with the United States, and forced out international inspectors at the site. Experts believe the complex can be used to produce several nuclear weapons within months.
The International Atomic Energy Agency's 35-nation board of governors planned to hold an emergency session Monday to review the nuclear crisis.
A senior nuclear agency official told The Associated Press on condition of anonymity that the IAEA almost certainly would refer the dispute to the U.N. Security Council later Monday -- a move that could lead to punitive sanctions or other actions against the reclusive nation's regime.
North Korea's top military brass vowed in a meeting in the capital, Pyongyang, on Saturday to increase the communist army's combat readiness. A separate statement from the official Korean Central News Agency accused the United States of trying to disarm the North and called the United States the "main obstacle" of Korean reunification.
But North Korea left open the possibility of other countries mediating the dispute -- an apparent nod to Seoul's diplomatic attempts.
"If there are countries which are concerned for the settlement of the nuclear issue on the Korean peninsula, they, proceeding from a fair stand, should force the U.S. to remain true to the international agreement so that it may discontinue its unilateral behavior," KCNA reported.
Japan and the United States have agreed to pursue a diplomatic end, Japan's Foreign Ministry said after telephone talks between Foreign Minister Yoriko Kawaguchi and Secretary of State Colin Powell late Saturday.
After his closed-door meeting with the Korean diplomat, Losyukov said it was important to get all sides to the negotiating table. He said both Moscow and Seoul opposed putting the issue before the Security Council "before other possibilities for negotiating have been used up."
Before the talks, Kim said Moscow's ties with Pyongyang could provide an "efficient channel for dialogue." Russian President Vladimir Putin has moved to reinvigorate Moscow's strong Soviet-era ties with North Korea.
Losyukov would not elaborate on possible ways out of the crisis, but Interfax quoted unidentified diplomats as saying that the possibility of offering "multilateral security guarantees" to Pyongyang in exchange for nuclear concessions was under discussion.
Kim later said such guarantees would have to include the United States.
Seoul's diplomatic offensive underlines its drive to mediate between its key ally, the United States, and its enemy, North Korea. But brokering a deal won't be easy.
The United States refuses to talk until the North scraps its nuclear programs. North Korea insists Washington must take the first step by signing a nonaggression pact.
Yim Sung-joon, South Korea's national security adviser, will visit Washington from Tuesday to Thursday to meet U.S. officials, then he'll visit Tokyo on Friday and Saturday, the presidential Blue House said.
Top U.S. officials will fly to Seoul later in the week and to Japan, South Korea and China later this month for more talks.
Michigan Sen. Carl Levin, the top Democrat on the Senate Armed Services Committee, urged the Bush administration to talk directly to North Korea to ease the tensions.
"That does not imply capitulation. It does not imply concessions. It just simply means face to face we are going to discuss the differences ... in order to avoid miscalculation," Levin said on Fox News Sunday.
White House and State Department officials had no immediate comment.
North Korea alarmed the world in October by admitting to a U.S. envoy that it had a secret uranium-based nuclear weapons program, in violation of a 1994 accord. The United States said North Korea already may have two nuclear weapons.
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.
One South Korean compromise being considered calls for the United States to resume oil shipments to North Korea, in return for the North abandoning its uranium nuclear development, media reported Saturday.
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.