The number of people killed in clashes in Syria between government security forces and supporters of ousted former President Bashar al-Assad has risen to 642, according to a monitoring group.

More than 1,000 people have been killed in clashes in the coastal provinces of Syria, according to one war monitoring group.

More than 800 civilians belonging to Syria's minority religious Alawite community have been killed in Syria's worst spate of violence since the ouster of long-time dictator Bashar al-Assad around three months ago,