BEIRUT - President Bashar Assad vowed on Friday to purge Syria of "extremist forces" he accused of assassinating a leading Sunni Muslim cleric who backed his two-year battle against rebels and protesters.
Assad made the pledge in a message of condolence over the death of Mohammed al-Buti, who was killed along with dozens of worshipers by an explosion in a Damascus mosque on Thursday.
State media put the death toll from the blast at 42, but the Syrian Observatory for Human Rights which monitors violence across the country said 52 people died and the final figure was likely to be more than 60.
The mass killing inside a place of worship shocked many Syrians, long accustomed to the daily bloodshed of a conflict which has killed 70,000 people, displaced hundreds of thousands of others and devastated whole districts of Syria's ancient cities.
The mosque bombing took place in the same Mazraa district of central Damascus where a car bomb killed more than 60 people one month ago, another sign that Syria's civil war had penetrated to the heart of Assad's capital.