Syria's army on Wednesday recaptured the only road into the government-held side of Aleppo city from Islamic State group fighters, state media reported, effectively breaking a nearly two-week-long siege.

The army gained full control of the route from the regime-controlled west of Aleppo to Khanasser, Ithriya and Al-Salmiyeh "after eliminating a number of Daesh (IS) terrorists," state television said.

Advancing IS forces had managed to cut off the route at the end of October despite Russian air support and a government offensive south of Damascus.

State TV said the road was now being demined and would be reopened to public traffic on Thursday.

The Syrian Observatory for Human Rights, a Britain-based monitor, said the frontline with IS had been pushed back about 10 kilometres from the route.

Aleppo was once Syria's economic hub, but has been ravaged by years of fierce fighting.

- Skyrocketing prices -

The city has been divided between government control in the west and rebel control in the east since shortly after fighting began there in mid-2012.

The main Aleppo-Damascus highway out of the city has been cut by rebels since then, but last year the army opened another route running through Khanasser to government-controlled Hama and Homs.

Its closure last month had left residents of west Aleppo stranded and sent the cost of basic goods in the sector skyrocketing.

Residents told AFP the roads were virtually empty because of fuel shortages, and several said they had been forced to cancel plans to travel abroad.

The IS advance was a blow to the regime as it seeks to capitalise on a Russian air campaign that began September 30 to regain momentum against a range of opposition forces.

Moscow says its strikes target IS and other "terrorists", but the opposition accuses Russia of focusing on moderate and Islamist rebels over jihadists.

Regime forces have launched ground offensives in Aleppo, Hama, Homs and Latakia provinces since the air campaign began, though they have so far registered modest advances.

They have also continued to pound the rebel-held Eastern Ghouta area outside the capital Damascus.

The Observatory said Wednesday at least 12 people, including a woman and a child, were killed in government shelling on Douma in the rebel region.

The town is the frequent target of regime fire, with at least 70 people killed there in government attacks last Friday.

Elsewhere, the Observatory said the toll in apparent Russian strikes on the IS-held town of Al-Qaryatain on Monday had risen to 23 civilians killed.

The group added that an unknown additional number of IS fighters had been killed in the same strikes.

The Observatory relies on a network of sources on the ground in Syria, including opposition activists and individuals in government-held territory.

The group says it distinguishes between strikes carried out by Syrian, Russian and US-led coalition aircraft based on flight patterns indicating whether planes took off from inside the country, as well as the type of planes and ordnance used.