Islamic State (IS) group jihadists killed 22 pro-regime fighters including 11 soldiers among them two officers, in surprise attacks in southern Syria on Friday.
Twelve jihadists also lost their lives in the assaults of Sweida, the Britain-based Syrian Observatory for Human Rights (SOHR) group said.
In an area with no IS presence it has been the first of its kind of attacks noted in more than a year, said the Observatory head.
The 22 pro-regime combatants killed also included nine Iranians and fighters belonging to pro-Iran Shiite militias, as well as two unidentified fighters, he said.
IS has ramped up its attacks against pro-regime forces since its fighters in May left their last stronghold near Damascus under an evacuation deal with the regime.
The new toll brings to 184 the number of pro-regime troops killed in more than two weeks of jihadist attacks across the country since May 22. At least 92 jihadists were killed during that same period.
IS in 2014 proclaimed a cross-border "caliphate" in Syria and neighbouring Iraq but has since lost most of that territory to separate offensives by Russia-backed regime troops and a US-backed Kurdish-Arab alliance.
The jihadists now control no more than three percent of Syria, the Observatory says, mostly in the eastern desert near the border with Iraq.
Earlier this week, IS assaults in the eastern province of Deir Ezzor killed 45 pro-regime fighters.
More than 350,000 people have been killed since Syria's conflict started in 2011 with the brutal repression of anti-government protests.