DAMASCUS, Syria (AP) -- President Bashar Assad vowed Friday to "wipe out" Muslim extremists in Syria, blaming them for a suicide bombing at a mosque that killed dozens of people, including a top cleric who supported the embattled regime in the civil war.
The death toll from Thursday night's bombing -- the first suicide attack on a mosque in two years of violence in Syria -- rose to 49 after seven of the wounded died overnight, the Health Ministry said.
Sheik Mohammad Said Ramadan al-Buti, a top Sunni preacher, was killed as he was giving a sermon in the mosque in the heart of the capital, Damascus. The blast, which also wounded nearly 80 other people, was one of the most brazen assassinations of the civil war, which has seen a number of suicide bombings blamed on Islamic extremists.
Al-Buti, 84, was the most senior religious figure killed in the civil war, and his slaying was a major blow to the president.
The preacher supported the regime since the early days of Assad's father and predecessor, the late President Hafez Assad, providing a Sunni cover and legitimacy to their rule. Sunnis are the majority sect in Syria while Assad is from the minority Alawite sect -- an offshoot of Shiite Islam. Al-Buti's grandson was among the dead.
In a statement on Syria's state-run SANA news agency, Assad said al-Buti represented true Islam in facing "the forces of darkness and extremist" ideology.
"Your blood and your grandson's, as well as that of all the nation's martyrs will not go in vain because we will continue to follow your thinking to wipe out their darkness and clear our country of them," Assad said.
Syria's main opposition group, the Syrian National Coalition, condemned the blast and expressed solidarity with the Syrian people, hinting that the bombing was the work of Assad's regime.
The Assad regime doesn't "hesitate to bomb mosques, universities, bakeries and residential areas with Scud missiles," said an English statement by the group. "This regime is not deterred by anything to carry out bombings, killing the Syrian people without guilt."
Syria's crisis started in March 2011 as peaceful protests against Assad's authoritarian rule. The revolt turned into a civil war as some opposition supporters took up arms the fight a harsh government crackdown on dissent. The U.N. says more than 70,000 people have been killed since.
In Geneva, the U.N.'s top human rights body on Friday extended its probe into suspected abuses in Syria. By a vote of 41-1, the 47-nation U.N. Human Rights Council reauthorized the investigation, which is being conducted by a panel of four independent experts, until March 2014, a half-year longer than originally proposed.
Those in favor of the extension included the United States, Germany, Libya, Pakistan, Qatar and United Arab Emirates. Only Venezuela was opposed. Abstaining were Ecuador, India, Kazakhstan, Philippines and Uganda.
Earlier this month, the panel, which began its work in August 2011, said it was collecting evidence on 20 alleged massacres in Syria, a reflection of the civil war's growing brutality.
An official at the ministry of religious affairs said al-Buti's funeral was scheduled for Saturday after the noon prayers. The government declared Saturday as a day of mourning and state-run Syrian TV halted its regular programs on Friday to air readings from the Muslim holy book, the Quran, as well as speeches of the late cleric.
In a speech earlier this month, al-Buti had said it was "a religious duty to protect the values, the land and the nation" of Syria. "There is no difference between the army and the rest of the nation," he said at the time -- a clear endorsement of Assad's forces in their effort to crush the rebels.
The mosque bombing also was among the most serious security breaches in Damascus. In July, an attack targeting a high-level government crisis meeting killed four top regime officials, including Assad's brother-in-law and the defense minister.
Last month, a car bomb that struck in the same area, which houses the headquarters of Syria's ruling Baath party, killed at least 53 people and wounded more than 200.
Elsewhere in Syria, activists reported shelling and clashes in the northern province of Aleppo, the suburbs of Damascus and the southern province of Daraa, where the uprising against Assad began.
The Britain-based Syrian Observatory for Human Rights said 15 people, including 11 rebels, were killed in the fighting in the Daraa region that borders Jordan. It added that three paramedics who work with the rebels were killed when their vehicle was hit in the provincial capital of Daraa that carries the same name.
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. The clashes between the Sunni neighborhood of Bab Tabbaneh, which supports Syria's rebels, and the adjacent Alawite neighborhood of Jabal Mohsen, which supports Assad, have repeatedly occurred in the past months.
Also in Tripoli, the Lebanese army said a soldier was killed and several others wounded when troops conducted a raid and captured several gunmen.
Lebanon is particularly vulnerable to getting sucked into the conflict in Syria. The countries share a complex web of political and sectarian ties and rivalries that are easily enflamed. Lebanon, a country plagued by decades of strife, has been on edge since the uprising in Syria began, and deadly clashes between pro- and anti-Assad Lebanese groups have erupted on several occasions.
Mroue reported from Beirut. Associated Press John Heilprin contributed to this report from Geneva.