SEOGWIPO, South Korea - China held back from joining the chorus of nations condemning North Korea over the sinking of a South Korean warship, making quick international sanctions unlikely but perhaps buying time while China quietly leans on its unpredictable, nuclear-armed neighbor.

As Chinese Premier Wen Jiabao met with his South Korean and Japanese counterparts Sunday, tens of thousands of North Koreans rallied in their capital, shouting slogans against South Korea and America.

South Korea has taken punitive measures against the North since a team of international investigators said this month that a torpedo fired by a North Korean submarine sank the warship Cheonan on March 26, killing 46 sailors. North Korea vehemently denies attacking the ship and has warned that the South is risking war by trying to punish it.

Beijing did not appear ready to support possible action in the U.N. Security Council against North Korea, its longtime ally. But Wen's closing remarks at Sunday's meeting seemed to signal that it was becoming more engaged in the crisis. "The urgent task for the moment is to properly handle the serious impact caused by the Cheonan incident, gradually defuse tensions over it, and avoid possible conflicts," Wen said.

Beijing has long tried to mediate disputes between the Koreas, and it often likes to maintain an appearance of neutrality. The Cheonan sinking poses an awkward challenge for China, which is under pressure to go along with sanctions but which wants to maintain its friendship with North Korea, an unpredictable buffer state whose collapse could cause instability on China's border.

China's unwillingness to criticize Pyongyang now might mean it is trying to use quiet negotiations to persuade North Korea to come clean about the Cheonan matter, one of the South's worst military losses since the Korean War.

If the matter of the sinking makes it to the United Nations, it is possible China will support sanctions, as it did last year when the global body punished Pyongyang for its nuclear programs. But it also could make sanctions impossible as a veto-wielding member of the U.N. Security Council.

After strategic talks in Beijing last week, senior U.S. officials predicted that China would gradually endorse the view that North Korea should be held accountable for the torpedo attack. Wen's next stop after Korea is Japan, where he is expected to face more pressure to censure North Korea.

In South Korea, Wen signaled that China was edging off the sidelines. He expressed condolences to the dead sailors' families and received an extensive briefing on the multinational investigation that blamed North Korea for the attack. Wen also told his hosts that China "will defend no one" once it determines who sank the ship.

South Korea plans to haul North Korea before the Security Council for sanctions or condemnation, but even if the South succeeds, it is unlikely Pyongyang will refrain from more provocative acts.