Airstrikes on villages and towns held by the Islamic State group in eastern Syria have killed and wounded dozens.
The airstrikes came a day after an attack by the extremists killed more than 120 pro-government fighters and briefly cut off the highway linking the capital Damascus with eastern Syria, opposition activists say.
It was not immediately clear if the airstrikes on areas including Mayadeen, Boukamal, Bouleil, Bouomar and Mushassan were carried out by the Russians or the US-led coalition. Syrian troops have been advancing in the eastern province of Deir el-Zour against IS under the cover of Russian airstrikes while the Kurdish-led Syrian Democratic Forces are marching against the extremists under the cover of airstrikes by the US-led coalition.
The airstrikes came after two days of clashes between Syrian government forces and their allies against IS fighters in central and eastern Syria that left nearly 200 dead on both sides. Syrian troops and their allies have regained most of the areas they had lost earlier.
The Britain-based Syrian Observatory for Human Rights said Saturday's airstrikes and those the night before killed 18 people, including two children and five women.
"They burnt Bouleil overnight," said Omar Abou Leila, of the monitoring group DeirEzzor 24, adding that 13 people were killed in Bouleil and nine others in Boukamal alone.
Activist said that airstrikes on rebel-held parts of northern Syria have stopped after more than a week of bombing that left hundreds of people dead or wounded, according to opposition activists. The attacks on Idlib and Aleppo came after militants launched an attack against government forces on September 19, capturing some areas before losing them.
The Observatory, which tracks Syria's war now in its seventh year, said that over the past two years the Russian military has killed more than 5700 civilians, 4258 IS fighters and 3893 others from insurgent groups.
