The U.S.-led coalition fighting the Islamic State in Syria and Iraq (ISIS) announced that a strike on Sunday killed Abu al Umarayn, a high-ranking leader who was involved in the murder of a former U.S. Army official.

Al Umarayn was killed in the drone strike alongside "several other ISIS members," the coalition announced. The ISIS leader in 2014 was involved in the beheading of U.S. Army Ranger Peter Kassig, whose death was captured in a video certified as authentic by U.S. officials, Fox News reported.

"Al Umarayn had given indications of posing an imminent threat to coalition forces, and he was involved in the killing of American citizen and former U.S. Army Ranger Peter Kassig," Army Col. Sean Ryan said in the statement. "He has been linked to and directly involved with executing several other prisoners as a senior ISIS member."

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Kassig was 26 years old when he was captured in October 2013. He was providing aid to Syrians fleeing the country at the time, Fox reported.

The U.S. has been conducting air strikes in Syria since 2014.

Human rights groups have lambasted the coalition for killing Syrian civilians during the strikes, which are aimed at driving ISIS forces out of their remaining territory in the country.