A wave of Russian airstrikes killed at least 21 ISIS extremists in the Syrian desert over the past 24 hours, the Britain-based Syrian Observatory for Human Rights said on Saturday.
The 21 were killed in at least 130 airstrikes "carried out over the past 24 hours by the Russian air force targeting the ISIS group in an area on the edge of the provinces of Aleppo, Hama and Raqqa", the Observatory said.
The raids, which continued into Saturday, follow a series of ISIS attacks Friday on regime and allied forces that killed at least eight members of a pro-Damascus militia, the monitor said.
In recent months, the vast desert, know in Arabic as the Badia, has been the scene of increasingly frequent fighting between the extremists and regime forces backed by Russian air power.
The extremists continue to launch attacks, mostly in the Badia desert which stretches from the central province of Homs to the border with Iraq.