A top aide to Abu Bakr al-Baghdadi, leader of the Islamic State of Iraq and Syria, has been killed in an airstrike in the extremist-held city of Mosul, al-Arabiya reported Thursday.

The Saudi-owned pan-Arab news channel, quoting the Iraqi Defense Ministry, said another ISIS figure also was declared dead in the strike.

Both U.S. and Iraqi warplanes have been conducting bombing raids in the area, and it was not immediately clear which nation had launched the strike.