BEIRUT -- Syrian President Bashar Assad vowed Friday to avenge the death of a senior pro-government cleric who was killed along with dozens of people in a suicide bombing at a Damascus mosque, saying he would "purge our country" of the militants behind the attack in the heart of the capital.
Both Mr. Assad and the rebels seeking to topple him blamed each other for Thursday's bombing at the mosque. At least 49 people were killed, including the 84-year-old preacher and his grandson, the government said, in one of the most brazen assassinations of the Syrian civil war.
Although the cleric was despised by the rebels for his unwavering support of the regime, opposition leaders condemned his killing.
Sheik Buti, Syria's best-known cleric and the most prominent religious figure killed so far in the conflict, had supported the regime since the early days of Mr. Assad's father and predecessor, the late President Hafez Assad, providing legitimacy to their rule. Sunnis are the majority sect in Syria, while Mr. Assad is from the minority Alawite sect -- an offshoot of Shiite Islam.
The opposition Britain-based Syrian Observatory for Human Rights put the death toll in the bombing at 52. No group claimed responsibility for the blast.
Sheik Buti's killing exposed weak links between the rebel fighters on the ground and their purported political leadership, and could boost the government's argument that Islamic extremists dominate the uprising.
In Amman, Jordan, President Barack Obama said Mr. Assad is sure to go eventually, but added that he was worried about Syria becoming a haven for extremists afterward. Standing beside Jordan's King Abdullah II, Mr. Obama said the international community must work together to ensure that there is a credible opposition ready to take over.
"Something has been broken in Syria, and it's not going to be put back together perfectly immediately -- even after Assad leaves," Mr. Obama said. "But we can begin the process of moving it in a better direction, and having a cohesive opposition is critical to that."
Sheik Buti's killing came near the start of the Syrian crisis' third year, with rebel and regime forces largely stalemated and an estimated 70,000 people dead. The opposition is trying to get organized enough to provide basic services to people in rebel-held areas and better coordinate the hundreds of independent groups fighting across Syria. Earlier this week, the coalition elected an interim prime minister.
Coalition members hope that U.S.-educated Ghassan Hitto will encourage world powers to back the rebels with badly needed funding and weapons. But so far, the coalition has failed to project its authority inside Syria or exercise control over the groups fighting Mr. Assad on the ground, many of them fueled by extremist ideologies and calling for an Islamic state. Most expect that it was one of those groups that killed Sheik Buti, reflecting how little control the opposition's exile leadership has over groups on the ground.
Sheik Buti's funeral is scheduled for today in Damascus following noon prayers. Mr. Assad declared it a day of mourning.
In neighboring Lebanon, pro- and anti-Assad gunmen fought in the northern port city of Tripoli, leaving six people dead and more than 20 wounded, according to state-run National News Agency. Clashes between the Sunni neighborhood of Bab Tabbaneh, which supports Syria's rebels, and the adjacent Alawite neighborhood of Jabal Mohsen, which supports Mr. Assad, have broken out repeatedly in recent months. Also in Tripoli, the Lebanese army said a soldier was killed in an army raid to capture several gunmen.