In addition, Iran has shipped hundreds of tons of military equipment, including guns, rockets, and shells, to Syria through the regular air corridor that has been established between Damascus and Tehran.

Intelligence officials believe the increased Iranian support has been responsible for the growing effectiveness of the Assad regime’s tactics in forcing anti-government rebel groups on the defensive…

The Iranian operation to support Mr Assad is being masterminded by Qassem Suleimani, the head of the Guards’ Quds force which is responsible for overseeing Iran’s overseas operations. The decision to increase Iran’s support for Syria was taken after the Syrian defence minister and Assad’s brother-in-law were killed in a suicide bomb attack at Syria’s national security headquarters in July, together with a number of other senior defence officials.