ELMENDORF AIR FORCE BASE, Alaska - China has signaled it could soon join the United States and others in rebuking North Korea for the sinking of a South Korean warship, senior American officials said Wednesday.

Speaking after talks in Beijing, the officials said China indicated it was prepared to hold North Korea accountable for the March 26 torpedo attack and could join in some kind of formal reprimand by the U.N. Security Council.

The move would represent a breakthrough for the White House, because publicly so far, China has resisted condemning North Korea for the incident, which cost the lives of 46 South Korean sailors.

China has long been North Korea's patron and ally, propping up Pyongyang's Stalinist-style regime with financial and military aid as well as diplomatic support.

On a visit to South Korea this weekend, Chinese Premier Wen Jiabao is likely to express regret for the deaths and hint that China will accept the results of an international investigation blaming North Korea, the U.S. officials said.

They spoke on condition of anonymity due to the sensitive nature of the discussions with China.

Wen is also expected to leave open the possibility of backing action against Pyongyang at the Security Council, although it was not clear how far Beijing was prepared to go.

In Seoul earlier Wednesday, U.S. Secretary of State Hillary Rodham Clinton said the world must respond to the "unacceptable provocation" represented by the sinking of the South Korean warship.

Clinton told reporters after talks with South Korean leaders that "the international community has a responsibility and a duty to respond" to the sinking, which "requires a strong but measured response." She spoke at a news conference with South Korean Foreign Minister Yu Myung Hwan.

Clinton did not say what that response should be, but two U.S. officials said the United Nations could take a variety of actions, ranging from tightening sanctions to a statement rebuking Pyongyang.

As one of five permanent members of the Security Council with veto authority, China can block any measure the United Nations tries to take.

Clinton spent hours discussing the sinking with top Chinese leaders during strategic and economic talks in Beijing on Sunday, Monday, and Tuesday, before spending a few hours in Seoul on Wednesday.

"I believe that the Chinese understand the seriousness of this issue and are willing to listen to the concerns expressed by both South Korea and the United States," she said in South Korea.

Tensions on the Korean peninsula have risen sharply since international investigators issued a report last week saying a North Korean submarine was likely responsible for the sinking of the Cheonan, a corvette patrolling the Yellow Sea.

South Korea began implementing punitive measures Tuesday - including slashing trade, resuming propaganda warfare, and barring the North's cargo ships from South Korean waters.

South Korea's navy also started two days of exercises off the country's western coast, near where the warship was sunk. The exercises will include anti-submarine operations, officials said.

The North Korean military, in turn, threatened to "completely block South Korean personnel and vehicles" from a jointly run industrial park in the North Korean town of Kaesong if the South resumed propaganda broadcasts across the border.

Clinton praised the investigation of the sinking as "very thorough, highly professional" and "very convincing." She said both the United States and South Korea had offered China "additional information and briefings about the underlying facts of that event."

China is not the only potential roadblock the United States and its allies face when it comes to pushing a tough response through the United Nations. Russia is another of the veto-holding Security Council members that must be persuaded to take action.

The Kremlin said in a statement Wednesday that President Dmitry A. Medvedev had sent a group of experts to Seoul to study the international investigation's findings.