BEIRUT (AP) — Airstrikes on villages and towns held by the Islamic State group in eastern Syria have killed and wounded dozens 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 said Saturday.

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 U.S.-led coalition. Syrian troops have been advancing in the eastern province of Deir el-Zour against IS under the...