Syrian troops backed by Hezbollah and Iranian fighters made advances on Saturday in their offensive to retake territory around the northern city of Aleppo from insurgents and jihadist fighters, a monitoring group said.

The campaign around Aleppo, which the army launched on Friday, is one of several assaults it has waged against rebel fighters since Russian jets began carrying out air strikes on September 30 in support of President Bashar al-Assad.

It has concentrated so far on clearing rebel areas south of Aleppo rather than the city itself, which is home to 2 million people and divided between government forces and rebels.

The Syrian Observatory for Human Rights said the army and its allies retook three villages amid fierce fighting in which at least 17 Islamist fighters and eight soldiers or allied forces were killed.

Troops are also trying to advance to the east of Aleppo towards Kweires military airport, aiming to break a siege on the base by Islamic State and other insurgents, the UK-based Observatory said.

Hezbollah's Al-Manar television said the army had captured the village of Huwaija, on the way to Kweires. The Observatory said it the army was advancing in Huwaija, one of several villages where heavy fighting was continuing.

The army and its allies have also been fighting to retake parts of the northern provinces of Hama, Idlib and Latakia seized by rebels in recent months, as well as insurgent areas north of Homs city, around the capital Damascus, and in the southern province of Deraa near the Jordanian border.

The Observatory reported fighting around the town of Talbiseh, part of a rebel-held enclave north of Homs city which has faced heavy bombardment by Russian jets for the last two weeks, and a ground offensive by the army and allied militias.

The monitor said that at least 72 people, including 31 children and women, were killed in the past 48 hours in the assault in Homs.