US military intervention in Syria unlikely without UN backing, Panetta says

While Syria is blaming rebel fighters for a weekend massacre in Houla, Defense Secretary Leon Panetta says he doesn't see the U.S. taking military action without the backing of the U.N. Security Council.

Panetta says his greatest responsibility is to make sure that if U.S. troops are deployed in any military role, that America has the support it needs from the international community.

His comments Thursday came a day after Susan Rice, the U.S. ambassador to the United Nations, suggested that some type of military intervention may be the only remaining option because diplomatic efforts so far have failed to remove Syrian President Bashar Assad from power.

"No, I cannot envision that," Panetta said when asked about military action without U.N. backing. Still he said that all options remain on the table and that the Pentagon is planning for "any contingency."

"But, ultimately, you know, the international community and the president of the United States are going to have to decide what steps to take," Panetta told reporters traveling with him to the Shangri-La Dialogue, a prominent defense conference in Singapore.

While he called the tumult in Syria an intolerable situation, his comments were more measured than other U.S. leaders Thursday, including Secretary of State Hillary Rodham Clinton, who lashed out at Russia for continuing its support of Assad.

Russia opposes military intervention in the country.

Syria on Thursday blamed up to 800 rebel fighters for the massacre in central Syria last week that killed more than 100 people, nearly half of them children, in its most comprehensive explanation to date of the bloodshed.

The narrative starkly contradicted accounts of witnesses who blamed "shabiha" or the shadowy gunmen who operate on behalf of President Bashar Assad's regime. The U.N. also said it had strong suspicions those pro-regime gunmen were responsible for much of the carnage on Friday in a cluster of villages known as Houla.

Rice dismissed the Syrian investigation's conclusion as "another blatant lie," telling reporters in New York "there is no factual evidence ... that would substantiate that rendition of events."

Facing international outrage over the killings, Damascus launched its own investigation into the deaths and announced that special prayers for the victims would be held at mosques across the country on Friday. The U.N. chief warned of civil war and pleaded with the regime to stop its attacks.

At a news conference Thursday, Qassem Jamal Suleiman, who headed the government's investigation into the massacre, categorically denied any regime role. He said hundreds of rebel gunmen carried out the slaughter after launching a coordinated attack on five security checkpoints.

The aim, he said, was to frame the government and to ignite sectarian strife in Syria.

"Government forces did not enter the area where the massacre occurred, not before the massacre and not after it," he said, adding that the victims were families who refused to oppose the government or carry arms.

A Houla-based opposition activist said it was clear that there had been no government investigation.

"The regime is looking for ways to justify the massacre to the world," said Saria al-Houlany. "It's clear that there wasn't any professional probe. ... If we had 800 fighters in Houla, this massacre would not have happened," he said.

The Houla massacre was one of the deadliest incidents since the uprising against Assad's hardline regime started in March last year. Activists say about 13,000 have been killed in 15 months.

The area is still under attack. The government focused its shelling Thursday on the Houla village of al-Tibeh. The activist group Syrian Observatory for Human Rights reported that some residents fled to nearby towns and villages "fearing a new massacre" as the area again came under fire.

Persistent bloodshed despite a cease-fire agreement has raised pressure on the international community to act.

Nearly 300 U.N. observers have been deployed around Syria to monitor a cease-fire that was supposed to go into effect on April 12 as part of a peace plan negotiated by international envoy Kofi Annan. But the plan has unraveled amid daily visit and the images from the Houla massacre caused outrage to spike.

The Associated Press contributed to this report.