Targets of Russian and Assad forces included six schools and two nurseries says Syria civil defence group

Eight school facilities were bombed in Idlib province, Syria, in a single day, as the battle for control of the country’s last opposition stronghold intensified.

The attacks came despite warnings that the violence had already led to the worst humanitarian crisis in the Syrian war to date.

Six schools and two nurseries in Idlib city, and the surrounding countryside, were among the targets of airstrikes by the Syrian regime and Russian forces on Tuesday. The attacks killed 21 people in total, the White Helmets civil defence service said.

Yousef Kashto, a teacher at al-Baraem school, in Idlib city, said the bombing began at 8am, and teachers decided to send the children home. As the pupils were leaving a cluster bomb hit the school yard, killing three teachers and a student, and severely injuring six others.

“We have been working under a state of emergency for two weeks due to the escalation in regime and Russian attacks on Idlib city … Two of our teachers are now in a critical condition. Parents rushed to the school horrified and looking for their children, who were still in shock,” he said.

At least 22 educational facilities have been bombed since the beginning of the year, according to the White Helmets and war monitors, and 400 civilians have been killed in total since Bashar al-Assad and his Russian allies began the blistering offensive on Turkish-backed rebels and jihadist groups in north-west Idlib province in December.

The UN says the violence has sent almost 1 million people fleeing north towards the Turkish border, which remains closed to refugees. Hundreds of thousands of families are now camped out in the winter conditions without adequate shelter, food or access to healthcare.

Seven children have died due to exposure to the cold and horrific living conditions in the informal settlements, according to Hurras Network, Save the Children’s local partner in Idlib.

Supported by Russian air strikes, over the last 48 hours pro-regime forces have managed to capture the town of Kafranbel, once a centre of Syria’s revolution, as well as 18 nearby towns and villages.

Turkey, which has deployed about 12,000 troops to Idlib to shore up a 2018 de-escalation deal agreed with Moscow, has repeatedly called on Assad and his Russian allies to pull back to the previous ceasefire line.

Also on Tuesday Syrian rebels, backed by the Turkish military, managed to seize the town of Nayrab, the first gain against the advancing Syrian government forces since Ankara entered the battle earlier this month.

The Turkish president, Recep Tayyip Erdoğan, has been pushing for a four-way summit with the leaders of Russia, France and Germany to address the escalating violence in Syria, but the Kremlin has so far remained non-committal.