Fighting broke out between Druze militias, Sunni Bedouin clans, and government forces, with some security units reportedly supporting Bedouin fighters. Israel said it struck several military vehicles in response to threats against the Druze minority near its border.
The Syrian Interior Ministry described the situation as a dangerous breakdown of order and confirmed the deployment of forces to the area.
According to the UK-based Syrian Observatory for Human Rights, the clashes have left more than 100 people dead.
Gunfire and smoke were seen over the region on Tuesday, hours after the Syrian defence minister declared a ceasefire following the entry of government forces into the city.