Up to 50 people have been killed in missile attacks on schools and hospitals in the region, the UN said.

Turkey's foreign ministry blamed Russia for the attacks. Moscow is yet to respond to the allegations.

Meanwhile, Syrian President Bashar al-Assad has cast doubt over plans to implement a "cessation of hostilities" in Syria.

Last week world powers agreed to work towards a selective truce in Syria, to begin later this week.

But in his first comments on the announcement, President Assad said such a ceasefire did not mean all the parties would put down their weapons.

"So far they say they want a ceasefire within a week," he said in televised comments.

"Who is capable of gathering all these conditions and requirements within a week?"

At least 12 people were killed in Azaz and the surrounding area, with two hospitals and two schools reportedly hit.

In Maarat al-Numan, in Idlib province, a hospital run by Medecins Sans Frontieres (MSF ) was reduced to rubble.

International humanitarian law bans any attack on patients and medical personnel or indeed any attack on medical facilities, which are zones that must be respected under the rules of war. Even if combatants take refuge in them, they should not be attacked

(BBC News)