The Pentagon says an Islamic State operative suspected of involvement in the 2012 attack on the U.S. diplomatic outpost in Benghazi, Libya, has been killed in a U.S. airstrike in Iraq.

Defense Department spokesman Col. Steve Warren says Ali Awni al-Harzi "operated closely" with Islamic State-associated extremists in North Africa and the Middle East. Warren says al-Harzi's death will diminish the radical group's ability to recruit North African jihadists into its fight in Syria and Iraq.

The Pentagon says al-Harzi was killed last week in Mosul, which fell to Islamic State forces a year ago.

The Sept. 11, 2012, attack on the U.S. outpost in Benghazi killed four Americans, including U.S. ambassador Chris Stevens.