At least 15 people are reported to have been killed and dozens wounded in a series of air strikes on rebel-held areas in the Syrian city of Aleppo.

One of the strikes hit near the Bayan hospital in the eastern Shaar district, activists and a monitoring group said.

Video footage, purportedly of the aftermath, showed bodies being pulled from burning and destroyed buildings.

It was not clear who was responsible, but government forces are seeking to regain control of the divided city.

In a defiant speech on Tuesday, Syrian President Bashar al-Assad promised to retake "every inch" of the country from his opponents.

Aleppo, he said, would be "the graveyard where the hopes and dreams" of Turkey's President Recep Tayyip Erdogan - a key backer of the rebels - would be "buried".

The speech to Syria's newly-elected parliament was Mr Assad's first major address since UN-brokered indirect peace talks in Geneva broke down in April.

Aleppo, once Syria's commercial and industrial hub, has been divided since 2012, with the government controlling the western half and rebel factions holding the east.

But in recent months, government forces backed by Russian air strikes have almost encircled the rebel-held areas and cut off one of the rebels' two routes to Turkey.

The battle for the city led to the collapse of a cessation of hostilities negotiated by Russia and the US, which supports the opposition, at the end of February.

The Local Co-ordination Committees (LCC), an opposition activist network, reported that Tuesday's air strikes had resulted in multiple casualties in the Maadi, Haidariya and Shaar districts.

The Independent Doctors Association, which describes itself as a cross-border Syrian humanitarian organisation, said an air strike had hit its children's hospital in Aleppo, destroying one floor.

Almost 740 medical workers have been killed in more than 360 attacks on hospitals and other medical facilities since the uprising against Mr Assad began five years ago, according to Physicians for Human Rights.

In April, an air strike blamed on government forces destroyed a hospital in Aleppo, killing at least 50 people including one of the city's last remaining paediatricians.

In a separate development, Syrian rebel forces recaptured several villages from the jihadist group Islamic State (IS) north of Aleppo, the Syrian Observatory reported.

IS militants seized the villages between the rebel-held towns of Marea and Azaz last month, cutting off a supply line to Turkey and forcing thousands of civilians to flee.

But on Wednesday morning, the militants reportedly withdrew to reinforce frontlines around the IS-held towns of Tabqa and Manbij, where government and US-backed Kurdish forces have launched offensives.