Zahran Alloush, leader of Jaysh al-Islam, one of the most prominent armed rebel groups in the suburbs of Damascus, was reportedly killed in a Russian airstrike Friday, according to Reuters.

The incident was reported by two rebel sources who say the attack was carried out by "Russian planes."

The airstrike focused on the Jaysh al-Islam (Army of Islam) headquarters in the Marj al-Sultan neighborhood in Eastern Ghouta, where Alloush had been attending a meeting between the groups top leadership, according to i24.

Eastern Ghouta, is a stronghold for Jaysh al-Islam, the largest rebel faction in the area, and as a result, is regularly bombarded by local government and Russian forces.

Though the attack has been reported by rebel sources, whether or not Alloush actually died in the attack is still unconfirmed, according to RT.

If true, Alloush who was ideologically at odds with more extremist groups like ISIS and al Queda, would become the latest rebel group leader to die in the ongoing Syrian conflict ever since Russia launched a major air campaign on September 30.

The rebel group attended an opposition summit in Riyadh on December 8 which produced a framework for peace talks with the government of President Bashar al-Assad.