BEIRUT (Reuters) – At least 30 people were killed at the weekend in clashes between residents in Homs, a human rights group said, the first reported factional fighting since protests against President Bashar al-Assad erupted in March.

Rami Abdelrahman, head of the Syrian Observatory for Human Rights, said on Monday that clashes between pro- and anti-Assad residents started on Saturday afternoon after the bodies of three government supporters, kidnapped last week, were returned to their relatives dismembered.

“At least 30 civilians were killed … they fell after civil fighting between pro and anti-regime (residents) started on Saturday,” the Observatory said in statement.

“These clashes are a dangerous development that undermines the revolution and serves the interests of its enemies who want to turn it into a civil war,” he said.

Homs, Syria’s third largest city, has been a focal point of the Syrian uprising since the military stormed the central city two months ago to try to crush street protests calling for Assad to step down after 11 years in power.

The city is a microcosm of Syria’s religious diversity with a Sunni Muslim majority living alongside minority groups, including Christians and Alawite Muslims, Assad’s own sect.

The anti-Assad protests started in Syria’s poorer Sunni rural areas, but quickly spread to cities which have more of a sectarian mix. More than 1,400 civilians have been killed since the uprising began, human rights organizations say.

Syrian authorities blame armed groups with Islamist links for the violence and say at least 500 policemen and soldiers have been killed since March.