A predawn U.S. military raid in northwestern Syria early on Wednesday targeted and killed a senior member of the Islamic State group, a U.S. official said.

It was the second known raid in northern Syria by U.S. troops since former President Bashar Assad was ousted in December. The Islamist-led government that replaced him has pledged to prevent a resurgence of the Islamic State group and is part of an anti-IS alliance that includes the U.S.-led coalition fighting the group.

The U.S. official, speaking on the condition of anonymity, said the raid killed a senior IS member who was seen as a candidate to be the leader of IS in Syria.