"Sheikh Abu Mohamed al-Adnani, the spokesman of the "Islamic State," was martyred while surveying operations to repel the military campaigns against Aleppo," Amaq news agency reported in a statement dated August 29.

The agency quoted a "military source" as confirming the man's death. It also said it would avenge the killing against the "filthy cowards in the sect of disbelief." The Associated Press also reported that the "Islamic State" (IS) released several audio files online, showing al-Adnani delivering fiery sermons urging supporters to stage attacks.

In January, Iraq reported that the IS spokesman had been wounded in an airstrike in Anbar, in western Iraq and moved to Mosul, the terror group's capital in the country.

Earlier this year, he called for Muslims to stage attacks in Western countries, urging believers in France to attack "the filthy French" and "crush them with your car."

Washington designated him "global terrorist" in early 2016 and he was one of the first foreign fighters opposing US forces in Iraq in 2003. He was also imprisoned by US troops, according to the think tank, Brookings Institution.

His role could be taken over by Iyad al-Obaidi, the IS treasurer, who also goes by the name of Saleh Haifa, security analyst Hisham al-Hashimi told Reuters news agency.

In recent times, the terror group has faced defeat in several regions in Syria, including the northern Aleppo province, where President Bashar Assad's forces, backed by Russia, are fighting rebel groups.

Last week, Turkish forces, together with Syrian rebels, drove out IS from Jarablus, on Syria's border with Turkey.

mg/kms (Reuters, AFP, AP)