ISIS confirms that its spokesman and senior commander has been killed while overseeing military operations in northern Syria.

FOX's Jon Decker has more from the White House:

The ISIS-run news agency said Abu Muhammad al-Adnani was killed in military campaign in the Syrian town of Aleppo.

Adnani has been the voice of ISIS over the past few years and has released numerous lengthy audio files online, urging followers to carry out attacks in Western countries.

ISIS has suffered a string of defeats in recent weeks, including in Aleppo and the Iraqi strongholds of Fallujah and Ramadi.

ISIS has vowed to take revenge for al-Adnani's death, who was at the top of the U.S. kill list. The U.S. had put out a $5 million reward for al-Adnani.

At the White House, Jon Decker, FOX News.