Benghazi attack suspect Ali Awni al-Harzi has been killed in an US airstrike in Iraq, the Pentagon says.

Ali Awni al-Harzi died on June 15 in the city of Mosul, which is controlled by ISIS, the Pentagon adds.

He was designated as a terrorist by the US Treasury and state department.

The US ambassador to Libya, Christopher Stevens, was among four Americans killed in the Benghazi attacks in September 2012.

US officials blamed the attack on militants linked to al-Qaeda.

The Pentagon described Ali Awni al-Harzi as “a person of interest” in the attack on the US compound.

It said he was an organizational intermediary who operated closely with extremists linked to ISIS or ISIL throughout North Africa and the Middle East.

“His death degrades ISIL’s ability to integrate North African jihadists into the Syrian and Iraqi fight and removes a jihadist with long ties to international terrorism,” Pentagon spokesman Colonel Steve Warren said.