The Obama administration is wrestling over whether to send an aircraft carrier to take part in military exercises with South Korea in what would amount to a significant show of force after the deadly sinking of a South Korean warship in March.

The back-and-forth over the USS George Washington reflects the precarious security situation in Northeast Asia following the North Korean sinking of the Cheonan on March 26. It underscores a huge issue facing U.S. and South Korean officials: how to stop North Korea, which is now believed to possess nuclear weapons, from conducting conventional attacks such as the torpedoing of the Cheonan.

Some within the administration are arguing that dispatching the 97,000-ton carrier to the Yellow Sea off the Korean Peninsula, where North Korea sank the Cheonan, could anger China or cause North Korea to react violently, according to officials involved in the discussions. But others insist that the United States needs to send a clear message to its allies and to North Korea and China that the United States is standing firmly behind the South.

"It's a very tough call," said Susan Shirk, a former State Department official and an expert on Asian security at the University of California at San Diego. "You don't want to be too proactive. But you need to send a clear message."

Reports that the United States would send the aircraft carrier battle group surfaced in early June following a decision by the United States and South Korea to conduct more intensive joint military exercises in response to the attack, which killed 46 South Korean sailors. At first, the two were planning anti-submarine warfare and anti-proliferation exercises, which wouldn't normally include an aircraft carrier. But then plans were apparently broadened.

On Friday, the Korea Times repeated earlier reports that the George Washington was being sent, citing an unidentified official at the Ministry of Defense. But a Pentagon spokesperson said that no decision had been made.

An international team of experts assembled by South Korea amassed overwhelming evidence that a North Korean mini-submarine sank the Cheonan with a torpedo.

Since then, South Korea has pushed the U.N. Security Council to take up the issue, cut most ties to North Korea and sought support from its neighbors to punish North Korea.

Still, Evan Feigenbaum, a former State Department official now at the Council on Foreign Relations, said that so far North Korea has faced few consequences for its actions.

While South Korea has received strong backing from Japan, China has been cool to its entreaties. China waited almost a month to offer condolences after the deaths aboard the Cheonan and has yet to accept the contents of the report. North Korea has denied involvement in the incident.

China's state-run press has also reacted badly to reports that the United States was considering dispatching the aircraft carrier to the Yellow Sea. "Having a U.S. aircraft carrier participating in joint military drills off of China's coast would certainly be a provocative action toward China," warned the Global Times, an English-language newspaper run by the Communist Party's mouthpiece, the People's Daily.

On Monday both North and South Korea briefed the U.N. Security Council on the incident and the security situation around the Korean peninsula, home to 28,500 U.S. troops. A day later, North Korea's U.N. ambassador, Sin Son Ho, warned that war might break out if the Security Council took strong action against it.

"If the Security Council releases any documents against us, condemning or pressuring us ... then myself as diplomat, I can do nothing," he said. "The follow-up measures will be carried out by our military forces."

Shirk and others said they backed the idea of sending the aircraft battle group.

"Our commitment to the region is always in question because we're the outside power," Shirk said. Add to that the appearance that China's economy has recovered quickly while unemployment is still high in the United States. "It just reinforces doubts about our ability to deliver," she said.