Head of major Syrian rebel group and several leaders are killed in Damascus airstrike

The leader of one of Syria's most powerful rebel groups is thought to have been killed yesterday in a Russian airstrike near Damascus.

Zahran Alloush, the head of Jaysh al Islam, one of the strongest insurgent faction in the rebel-held suburbs of Damascus, was killed in an air raid that targeted his group's headquarters.

They said a secret headquarters of the group, which is the largest rebel faction in the area and has thousands of fighters, was targeted by what they described as Russian planes.

Zahran Alloush, (second left) the head of Jaysh al Islam, one of the strongest insurgent faction in the rebel-held suburbs of Damascus, was killed in an air raid that targeted his group's headquarters

Several leading members of the group were killed after a meeting east of Damascus was targeted, the Syrian Observatory for Human Rights said.

'A number of members and leaders of the Army of Islam were killed, but the fate of the commander, Zahran Alloush, is unknown,' the monitoring group said.

It was not immediately clear who had carried out the air strike but Russian forces were most likely.

Russia's air force has made 5,240 sorties since it started the strikes in Syria on September 30, including 189 sorties on Thursday alone, Russia's defence ministry told reporters yesterday.

Long-range strategic bombers have carried out 145 sorties over the same period, Sergei Rudskoi, a department chief at the General Staff of the armed forces, told a news briefing in Moscow.

Jaysh al Islam, with thousands of trained fighters, is the biggest and seen as the most organised rebel group. It has been effectively running the administration of Eastern Ghouta

Several leading members of the group were killed after a meeting in Eastern Ghouta, a suburb of Damascus was targeted, the Syrian Observatory for Human Rights said

Several rebel group leaders have been killed since Russia began the major aerial campaign in support of its ally Syrian President Bashar al-Assad, whose troops earlier in the year had suffered a series of setbacks.

Jaysh al Islam, with thousands of trained fighters, is the biggest and seen as the most organised rebel group. It has been effectively running the administration of Eastern Ghouta.

Before setting up Jaysh al Islam, Alloush had founded Liwa al-Islam, or the Brigade of Islam, with his father Abdallah, a Salafist Syrian cleric based in Saudi Arabia.

Alloush was ideologically at odds with ISIS and al Qaeda, espousing a more moderate brand of Islam. However he rejected democracy and also called for the killing of Shiites and Alawites.

Amnesty International claims at least 200 civilians were killed in Russian air strikes in Syria in the two months to the end of November,

The human rights group also accused Russia of using cluster bombs in civilian areas and says such attacks could constitute war crimes.

Russia's defence ministry dismissed the report as containing 'fake information' and 'trite cliches'.