Rebel Syrian fighters detonate tunnel bomb underneath key industrial district

Members of a rebel Syrian fighter group have boasted the brutal effect a tunnel bomb they detonated had on an industrial area of the city of Aleppo.

The tunnel bomb was set off over the weekend underneath the Ramousah district by the Free Syrian Army (FSA) - a Syrian opposition group whose goal is to topple the Assad government.

The FSA have links with the newly formed Islamist group Jabhat Fatah al Sham, formerly the al Qaeda-linked Nusra Front, and Ahrar al Sham.

In the video posted online, rebel fighters are seen walking through the tunnel and talking to the camera in Arabic. Vision then cuts to the explosion above ground.

It is unknown exactly how many people were killed in the attack.

Syrian forces have fought back with the assistance of Russian air strikes.

"We are now overlooking the Ramousah area but Russian jets are intensifying their bombing, which is holding us back from moving quickly," a rebel commander told Reuters.

Another rebel officer claimed 10,000 of their troops, at least 95 tanks and several hundred rocket launchers had been deployed for what he is calling the "great epic battle of Aleppo".

He claimed scores of suicide bombers were preparing to drive military vehicles packed full of explosives into army posts.

Rebel forces are attempting to reclaim a strip of government-controlled territory to reconnect them with other rebel-held areas.

Aleppo was formerly Syria's biggest city before the conflict broke out five years ago and has been divided between government forces and rebels since then.