The fight between Syrian fighters and ISIS has claimed over 90 lives.
According to a war monitor, the Syrian Desert clash between the pro-government forces and holdouts of the Islamic State group have killed at least 90 combatants this month.
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.
AFP reports that at least 10 government loyalists and 13 IS jihadists were killed over the past 24 hours alone, Observatory head Rami Abdul Rahman said.
“IS is trying to prove that it is still strong,” he added.
Mobile IS units have remained active in the Syrian Desert, known in Arabic as the Badia, since the jihadists lost the last shred of its self-proclaimed caliphate in March last year.
September clashes killed 13 pro-government fighters and 15 jihadists, while in early July 20 pro-government fighters and 31 jihadists were killed over two days.
In August, IS claimed an attack, presumably mounted from the desert, that killed a Russian general near the Euphrates valley city of Deir Ezzor.