One of the most powerful rebel leaders of Syria has been killed in an airstrike in the eastern suburbs of Damascus. A rebel source close to The Guardian has confirmed this development.

Zahran Alloush, 44, head of powerful Syrian rebel group ‘Jaish al-Islam’ (Army of Islam) was reported dead by Reuters initially. ‘Jaisl al-Islam’ is one of the largest opposition groups in Syria that have thousands of fighters who hold ground near Damacus.

The Syrian state news agency said that Alloush was in the eastern Ghouta region, where he was killed along with five other senior leaders. Three aircrafts had targeted a “secret meeting” of commanders which was supposed to take place in eastern Ghouta, according to the Syrian Observatory for Human Rights (SOHR). The SOHR have been widely regarded as the eyes of Syria with a wide range of contacts across the country.

The Syrian government and its media have always considered ‘Jaish al-Islam’ as “Terrorists” and the news of its death was announced on various state television channels. The death was a “special operation” by the Syrian Army as a part its “national mission.” Top military commander, Abu Hammam al Buwaidani, supposedly master minded this operation.

A host of Syrian rebels and its leaders have been killed since Russia launched its mission to eradicate the Islamic State on September 30. A Syrian security force also told AFP that “dozens” of other rebels have also been killed alongside Alloush, with the missiles provided by Russia to the Syrian army.

The final report says 12 members of ‘Jaish al-Islam’ and 7 from the ‘Islamist Ahrar al-Sham’ group were killed.

Analyst Charles Lister tweeted that this death “stands as one of the most significant opposition losses” of Syria’s nearly five-year rebel uprising.

“In a way, Zahran Alloush has been the rare successful centraliser in the Syrian rebel movement,” said Aron Lund, editor of the Carnegie Endowment’s Syria in Crisis website.

But with Alloush gone, that cohesion could “unravel” he added.