Clashes in the Syrian Desert between pro-government forces and holdouts of the Islamic State group have killed at least 90 combatants this month, a war monitor said on Wednesday.
Russian aircraft carried out strikes in support of their Syrian regime ally, the Syrian Observatory for Human Rights said.
The clashes broke out in two separate areas of the vast desert that separates the Orontes valley in the west from the Euphrates valley in the east.
The government side lost 41 dead, the jihadists 49, the Britain-based war monitor said.
At least 10 government loyalists and 13 IS jihadists were killed over the past 24 hours alone, Observatory head Rami Abdul Rahman said.