Washington, Nov 15 (PTI): A US airstrike has killed the leader of the Islamic State group operating in Libya, the Pentagon has said.

On November 13, the US military conducted an airstrike in Libya against Abu Nabil, also known as Wissam Najm Abd Zayd al Zubaydi, an Iraqi national who was a longtime Al-Qaeda operative and the senior ISIS leader in Libya, Pentagon Press Secretary Peter Cook said.

Cook said reporting suggests Nabil may also have been the spokesman in the February 2015 Coptic Christian execution video.

"Nabil's death will degrade ISIS's ability to meet the group's objectives in Libya, including recruiting new ISIL members, establishing bases in Libya, and planning external attacks on the US," Cook said.

"While not the first US strike against terrorists in Libya, this is the first US strike against an ISIS leader in Libya and it demonstrates we will go after ISIS leaders wherever they operate," he said.

Cook however noted that this operation was authorised and initiated prior to the terrorist attack in Paris.