More than 1,300 schools have been totally destroyed in government-held areas of Ukraine since Russia’s 2022 invasion and others have been badly damaged, the UN children’s fund UNICEF said on Tuesday.

Persistent attacks mean that only about a third of school-age children there are attending classes fully in person and many are forgetting what they have already learned, it said.

Beyond Ukraine, more than half of the children whose families have fled the conflict to seven countries are not enrolled in national education, UNICEF said, citing language barriers and overstretched education systems.

Some schools have suffered direct hits and others have closed down as a precaution in 18 months of missile and artillery attacks on residential areas across the country.

“Inside Ukraine, attacks on schools have continued unabated, leaving children deeply distressed and without safe spaces to learn,” it said.

The war followed COVID disruptions, meaning some Ukrainian children were facing a fourth consecutive school year of disruptions as they return to classes this week after the summer break, UNICEF said.

“Not only has this left Ukraine’s children struggling to progress in their education, but they are also struggling to retain what they learnt when their schools were fully functioning,” said Regina De Dominicis, UNICEF Regional Director for Europe and Central Asia.

Around half of Ukraine’s teachers have reported a deterioration in students’ abilities in language, reading and mathematics, it said, and they have missed out on the sense of safety and friendships school can provide to those enduring war.