DAMASCUS, Oct. 18 -- The Syrian army forces backed by Russian airstrikes and Iranian militias have advanced in the southern countryside of the northern province of Aleppo, as part of the broad offensive the military general command declared recently, a military source told Xinhua on Sunday.

The Syrian army has expanded its control over several areas in the southern countryside of Aleppo, becoming closer to the rebel-held Thermal Station of Aleppo, which is crucial for feeding it with electricity, and the besieged Koerse airbase in the southeastern countryside of Aleppo.

The army is also fighting to reach the eastern rebel-held district of Rashidin, the place where the rebels fire most of their mortar shells and improvised rockets into the government-controlled part west of Aleppo.

The source said the military operation in Aleppo aims to isolate the rebels in the countryside of Aleppo and cut their supply lines from the outskirts of Aleppo toward the rebel-held areas, which are adjacent to the government controlled part.

The source said the Russian warplanes, which have been striking the terror group's positions in Syria since late September, are striking the rebel-held areas in the northern countryside of Aleppo, near the Turkish borders.

He said the broad military operation in the central and northern region in Syria aims primarily to secure the international road connecting Aleppo with the southern region and the capital Damascus by securing and recapturing several towns and villages in the central region, mainly in the central province of Homs and Hama.

The Syrian leadership is working to recapture its sway in Aleppo, Syria's second-largest city and once an economic hub.