BEIRUT - In a dramatic twist in the nine-month uprising against Syrian President Bashar al-Assad, government officials said Friday that two suicide car bombers detonated hundreds of pounds of explosives in front of buildings used by intelligence agencies in the heart of Damascus, the capital.

Officials quickly pointed the finger at al-Qaeda, saying the dramatic escalation in violence confirmed their contention that armed terrorists are behind the unrest.

To reinforce the point, state television broadcast video of mangled body parts, burned-out vehicles, and bloodied pavement against an action-movie-like soundtrack. The Interior Ministry said 44 people were killed and 166 injured.

But many opposition activists accused the government of staging the entire scene for an advance team from the Arab League, which had arrived hours earlier to prepare for an observer mission to determine whether Syria is fulfilling its pledge to end a deadly crackdown on antigovernment protesters who have been holding major demonstrations since March.

The Local Coordination Committees, a network of activists who organize protests and report on the violence, said security forces killed as many as 21 people Friday, as thousands took to the streets after midday prayers in opposition strongholds.

The wildly divergent accounts were a pointed reminder of how difficult it is to obtain credible information about an uprising with competing narratives and few, if any, independent observers.

Most international journalists have been barred from entering Syria, leaving them to piece together events from amateur videos, Facebook postings and conversations over shaky Skype connections with activists who rarely distinguish between fact and rumor.

The timing of the twin blasts, which happened minutes apart and could be heard across Damascus, was bound to raise suspicion among anti-government activists.

Syria has been under mounting pressure to end the bloodshed, which the United Nations says has killed more than 5,000 people. There have been calls for international intervention, a prospect certain to raise alarm among regime insiders just months after a Western-led military campaign in Libya helped topple the late despot Moammar Gadhafi.

The Arab League, which last month suspended Syria and imposed sweeping sanctions, has threatened to go to the U.N. General Assembly if Syria does not comply with a regional peace initiative calling on Assad's government to withdraw its forces from cities and towns, release political prisoners, open negotiations with its opponents and admit monitors. The first observers are expected to arrive within days.

Syrian officials brought the league's advance team to the site of Friday's bombings in Kfar Sousa, an upscale neighborhood of Damascus, and addressed reporters outside the headquarters of the General Intelligence Agency, where bodies remained on the ground.

"We said it from the beginning, this is terrorism," Deputy Foreign Minister Faysal Mekdad said. "They are killing the army and civilians."

The government says more than 2,000 security-force members have been killed defending Syria against Islamic extremists and armed gangs.

The head of the league's advance team, Samir Seif al Yazal, said, "What we are seeing today is regretful."

The U.N. Security Council and the United States condemned the bombings.

"There is no justification for terrorism of any kind, and we condemn these acts wherever they occur," State Department spokesman Mark Toner said. A U.S. official with access to intelligence declined to speculate about who might be responsible, saying, "For the moment, it's unclear."