The headteacher of a primary school where two of its classes were gutted by fire has spoken of how its community has been "devastated" by the blaze.
The fire tore through a nursery areas and the classroom used by Year 3 at Rift House Primary School in Masefield Road, Hartlepool, at around 6pm last night.
Today, only Year 6 pupils have gone to school so they can sit their SATs exams.
An investigation is under way by Cleveland Police and Cleveland Fire Brigade into the cause of the fire.
No arrests have been made, but police have now said they believe the fire was started by one or several people.
The school's headteacher David Turner said: “Everyone is devastated by the fire which has destroyed the school nursery and Year 3 classroom which were located in an annex next to the main school building.
“We had to close the school today apart from Year 6 pupils who attended to take their SAT papers.
"The school will remain closed tomorrow to all pupils apart from Year 6 and a further update will follow soon
“The support from staff, parents, children, the council, emergency services and education colleagues has been fantastic and I cannot praise everyone enough for helping out during our moment of need.”
Acting Detective Inspector Chris Stoddart, of Cleveland Police, said: “The damage caused will mean great inconvenience to the school and is likely to bring huge repair costs.
“I would appeal to anyone who saw anyone in or around the school yesterday afternoon, or anyone who has information which could help identify the person or people responsible for the fire to contact Cleveland Police on 101.
“We are following up various pieces on information passed to police and the person or people responsible should think about coming forward before we knock on their door.”
Fire crews from Hartlepool, Middlesbrough and Thornaby stations attended the scene, with roads closed off to help them battle the blaze.
Anyone with information can contact police via 101 or anonymously to the independent charity Crimestoppers via its website at www.crimestoppers-uk.org or by phoning 0800 555 111.