The Britain-based Syrian Observatory for Human Rights said an airstrike hit an Islam Army meeting near the Damascus suburb of Otaya today killing several officials including Allouch.
The Local Coordination Committees said Allouch was killed by a Russian airstrike in al-Marj area near Damascus.
The Lebanon-based AL-Mayadeen TV said Allouch was killed during a meeting to reconcile two feuding militant factions near Damascus. The station said 13 airstrikes hit eastern Damascus today.
Saudi-backed Allouch is one of the most powerful rebel commanders and his group controls large parts of the Damascus suburbs.