Rayan Meshaal's brother said in Facebook post that Meshaal and his daughter were killed at their home in al-Mayadin
An air strike by the US-led coalition has killed the founder of the Islamic State (IS) group’s propaganda media outlet Amaq in the eastern Syrian province of Deir al-Zor, his brother said in a Facebook post on Wednesday.
Reuters could not independently confirm his death and there was no immediate comment from the US-led coalition against IS.
The post said the strike killed Rayan Meshaal and his daughter in their home in the city of al-Mayadin. Syrian opposition activists had been sharing news of Meshaal's death on social media.
"I'm pleased to announce the martyrdom of my older brother Baraa Kadek, known as Rayan Meshaal...in an air strike by the coalition," the Facebook post reportedly by his brother said.
IS often claims responsibility for attacks worldwide through Amaq channels on social media.
Rita Katz, director of the US-based SITE monitoring service, said on Twitter that a coalition strike allegedly killed Meshaal in Deir al-Zor.
Katz added Amaq had "shown itself as ISIS' state media agency" since its founding in 2014 and had issued claims for at least two dozen attacks around the world.
IS militants control swathes of Syria's vast eastern deserts and most of Deir al-Zor province bordering Iraq, but they have been on the defensive over the past year.
With air strikes and special forces on the ground, the US-led coalition is supporting an alliance of Kurdish and Arab militias in a campaign to capture Raqqa city.