At least 46 people have been killed in suspected Russian air strikes on several areas of Idlib province in northwest Syria, the Syrian Observatory for Human Rights said, as regime forces advanced in fierce clashes with revolution fighters in east Aleppo.

The Britain-based monitor said on Sunday at least three locations were bombed in the northwestern province and most of the casualties were civilians.

At least 26 people, including three children, were killed in the town of Kafr Nabl, and another 18 people were killed in the town of Maarat al-Numan.

A witness told AFP news agency "six strikes hit houses and a crowded local market" in the village of Kafr Nabl.

In Maarat al-Numan, an AFP photographer saw local residents and White Helmets rescue workers trying to reach survivors in the rubble at a vegetable market hit in the strike.

The monitor also reported two additional deaths, one in an earlier strike on Maarat al-Numan and another in al-Naqir, also in Idlib.

And it said six civilians, four of them children, had been killed in a regime barrel bomb attack on the town of al-Tamanah in the south of Idlib.

The northern Idlib province is mostly controlled by a powerful opposition alliance known as the Army of Conquest.

Most of Homs province is controlled by the Syrian regime, but small parts of the countryside are controlled by a range of opposition groups.

PHOTO CAPTION

Men inspect damaged motorcycles after an airstrike on a market in the town of Maarat al-Numan in Idlib province, Syria April 19, 2016. REUTERS

Al-Jazeera