U.S.-led airstrikes targeted Syrian oil installations held by the militant Islamic State group overnight and early Thursday, killing nearly 20 people as the militants released dozens of detainees in their de facto capital, fearing further raids, activists said.
The latest strikes came on the third day of a U.S.-led air campaign aimed at rolling back the Islamic State group in Syria, and appeared to be aimed at one of the militants' main revenue streams. The U.S. has been conducting air raids against the group in neighboring Iraq for more than a month.
The Islamic State group captured most of Syria's largest oil fields earlier this year and is believed to be partly funding its operations by smuggling oil out and selling it on the black market.
At least four oil installations and three oil fields were hit around the town of Mayadeen in the eastern province of Deir el-Zour, according to the Britain-based Syrian Observatory for Human Rights and two local activist groups. A third activist group loyal to the militants confirmed the reports.
At least 14 militants were killed, said the Observatory, which gathers information from a network of activists on the ground. Another five people who lived near one of the refineries in the northeastern Hassakeh province were also killed, the Observatory said, adding that they were likely the women and children of the militants.