Chemical weapons experts have determined that mustard gas was used in a Syrian town where Islamic State insurgents were battling another rebel group, according to a report by an international watchdog seen by Reuters. A confidential Oct. 29 report by the Organisation for the Prohibition...

Britain said on Thursday there was a significant possibility that Islamic State's Egyptian affiliate was behind a suspected bomb attack on a Russian airliner that killed 224 people in the Sinai Peninsula. Russia dismissed the claim as speculation and Egypt said there was no indication so...

Moscow's military force in Syria has grown to about 4,000 personnel, but this and more than a month of Russian air strikes have not led to pro-government forces making significant territorial gains, U.S. security officials and independent experts said. Moscow, which has maintained a...

 Airstrikes believed to have been carried out by Russian warplanes on an ISIS-held town in central Syria killed 23 civilians, an activist group said Wednesday. Among those killed in the Monday strikes on the Homs province town of Al-Qaryatain were three children and a woman, the Syrian...