The Syrian government's security forces sent to restore order in Sweida have also become embroiled in clashes with local groups.
Several of the 89 killed in the clashes were from the Syrian Ministry of Defense, according to the UK-based Syrian Observatory for Human Rights (SOHR).
According to SOHR, the violence – in which Bedouins and local fighters clashed – began after a series of kidnappings between the two groups.
The majority of the population in the city of Sweida are Druze. 50 of the 89 dead are reported to have been residents of the city, including two children.
Reports of the number of dead vary.
Israel reported on Monday that the country's military had struck military tanks in southern Syria. Israel has previously threatened to intervene in Syria to defend the Druze religious minority.
The violence is the first to result in fatalities since Druze and security forces clashed in May, resulting in dozens of deaths. SOHR describes the escalation as "dramatic".
