A U.S. Special Operations assault force captured an ISIS operative during a recent raid in northern Iraq, a U.S. official confirmed to Fox News on Tuesday.

The official would not discuss specifics of the raid, including the identity of the captured militant, due to the sensitivity of the mission. The operation was first reported on by CNN. A report in The New York Times described the operative as a “significant” member of the terror group.

In December, Defense Secretary Ash Carter announced that a special operations task force was headed to Iraq. Fox learned the 200-man unit, which included an assault force, intelligence cell and aviation element would be based in Irbil in northern Iraq.

In October, Army Master Sgt. Joshua Wheeler, a Delta Force Commando, was killed during a mission to rescue of dozens of mostly Kurdish prisoners held by ISIS in northern Iraq.