A U.S.-led coalition airstrike in eastern Syria has killed the founder of the Islamic State (ISIS/ISIL) propaganda arm known as the Amaq News Agency, according to activists and his brother.

Agence France-Presse (AP) reports:

Rayan Mashaal, also known as Baraa Kadek, was reportedly killed in coalition bombardment on the IS-held town of Mayadeen, near Syria’s border with Iraq, on Monday. Several Syrian activist Facebook pages, including the prominent media collective Eye on the Homeland, shared the news of his death.

Mashaal’s brother also reportedly confirmed his death through a Facebook post.

“I’m pleased to announce the martyrdom of my older brother Baraa Kadek, known as Rayan Meshaal… in an air strike by the coalition,” reportedly wrote the brother, identified as Hozaifa, on Facebook.

However, neither the U.S.-led coalition nor ISIS has confirmed the jihadi propagandist’s death.

ISIS often uses Amaq to disseminate its propaganda and take responsibility for attacks.

“The militant group itself has not reported the death of the founder of Amaq news agency, Baraa Kadek,” notes the Associated Press (AP). “But his brother, Hozaifa, posted on his Facebook that Kadek and his young daughter were killed in an airstrike in Mayadeen town in Deir el-Zour province.”

“Other Syrian opposition news outlets, including Halab News Network and Qasioun news agency, reported Kadek’s death late Wednesday,” it continues. “But it was not immediately clear where Kadek was killed or when. His brother said he was killed in his home.”

The U.S.-led coalition has been trying to dismantle ISIS’s successful online media operations, which the jihadist group aptly uses as a recruiting tool and to spread its influence.

In April, ISIS eulogized a French-born U.S./Syria dual citizen who had been wanted by the FBI and considered a recruiter and essential operative in the jihadist group’s media efforts.

A U.S.-led coalition airstrike killed American college graduate Ahmad Abousamra, 36, back in January. He was the founder of ISIS’s propaganda magazine Rumiyah.

Rita Katz, the chief of the SITE monitoring service, which tracks jihadi websites, wrote on Twitter that a U.S.-led coalition strike allegedly killed Meshaal in Syria.

The Amaq News Agency had “shown itself as ISIS’ state media agency” since its founding in 2014 and had claimed responsibility for at least two dozen attacks around the world, she added.

Under assault by U.S.-backed local forces, including Kurdish fighters and Iran-allied Shiite militias, ISIS is losing ground in both Syria and Iraq.