About 300 men working for a Kremlin-linked Russian private military firm (Wagner Group) were either killed or injured in Syria last week, according to three sources familiar with the matter. ...A U.S. official, speaking on condition of anonymity, said last week that a force aligned with Assad, backed with artillery, tanks, rockets and mortars, had on Feb. 7 attacked fighters with the U.S.-backed Syrian Democratic Forces near Deir al-Zor. U.S. special forces were accompanying the SDF forces that came under attack, officials in Washington said. The U.S.-led coalition in Syria retaliated, killing about 100 of the pro-Assad forces, according to...