Three days of clashes in Syria have left more than 700 people dead in the worst bout of violence since the Assad regime was ousted last December, according to a war monitoring group.

The fighting began on Thursday and ended early Saturday, said the Syrian Observatory for Human Rights, when Sunni Muslims loyal to the new regime launched a spate of revenge killings against members of Bashar al-Assad’s minority Alawite sect.

The organisation estimates that 532 Alawite civilians were killed in the attacks.

The overall toll on Thursday reached 745, after fighting killed 93 members of the new government’s security forces and 120 pro-Assad fighters, according to the Observatory.

The killings followed clashes sparked by the arrest of a wanted suspect in a predominantly Alawite village, the Observatory reported.