Moscow is claiming that a Russian airstrike killed ISIS spokesman and key figure Abu Mohammed al-Adnani in Syria on Tuesday. According to Russia’s defense ministry, he was one of 40 rebels who were killed by Russian bomber planes in Maaratat-Umm Khaush, in the Aleppo province.

The U.S., on the other hand, calls the claim preposterous–one U.S. defense official told Reuters, speaking on condition of anonymity, that “Russia’s claim is a joke.”

The U.S. also conducted an airstrike targeting al-Adnani on Tuesday, but has not confirmed whether he was killed. One official said of Russia’s claims to CNN: “It would be laughable but for the very real humanitarian suffering Russia has inflicted.” He added: “We conducted a strike that targeted al-Adnani. We are assessing the results of that strike.”

The official spokesman of ISIS and one of its most senior members has died https://t.co/tXFjE27j1Q pic.twitter.com/646KFp3oLF

— CNN International (@cnni) August 31, 2016

On Tuesday, ISIS announced on its own news agency Amaq that al-Adnani had died during an inspection of military operations. The cause of death was not revealed, but ISIS members said they are determined to seek revenge. They said:

To the filthy and coward nonbelievers and to the holders of the Christ emblem, we bring the good news, which will keep them awake, that a new generation in the Islamic State … that loves death more than life … this generation will only grow steadfast on the path to Jihad, stay determined to seek revenge and be violent toward them.

If al-Adnani is dead, it would mean a significant blow to the terrorist organization. He was one of the remaining founding members and a visible one in his role as ISIS spokesman. He’s been responsible for attacks abroad–Al-Adnani was probably the commander behind the terror attacks in Paris in 2015, and has been encouraging lone wolf attacks on civilians. He was also the right hand of ISIS leader Abu Bakr al-Baghdadi.

“He absolutely tried to maximize every opportunity to instill fear in Syria and Iraq and the international community and send fighters overseas to attack,” said CNN correspondent and diplomatic editor Nic Robertson.

Recent advances by Iraq and its allies toward the city of Mosul, where ISIS has its most important foothold, combined with the U.S. coalition cutting ISIS off from the border of Turkey has put pressure on the group. A U.S. counter terrorism official said that if al-Adnani is indeed dead, it would hurt the Islamic State “in the area that increasingly concerns us as the group loses more and more of its caliphate and its financial base … and turns to mounting and inspiring more attacks in Europe, Southeast Asia and elsewhere.”

Emma Von Zeipel

Emma Von Zeipel is a staff writer at Law Street Media. She is originally from one of the islands of Stockholm, Sweden. After working for Democratic Voice of Burma in Thailand, she ended up in New York City. She has a BA in journalism from Stockholm University and is passionate about human rights, good books, horses, and European chocolate. Contact Emma at EVonZeipel@LawStreetMedia.com.

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