A large fire which has closed a secondary school is being treated as suspicious.
Dozens of firefighters were called out to Sherburn High School, in Sherburn, North Yorkshire, just before midnight on Monday.
The school said the gymnasium and changing block had been damaged but no-one was in the building at the time.
North Yorkshire Police said it launched a full inquiry and was checking forensic analysis and CCTV.
Insp Ian Mcniff said: "Officers have been investigating the circumstances surrounding the fire at Sherburn High School and investigations have now led us to believe the origin of the fire is suspicious."
The blaze has been scaled down but two crews remain on the scene, North Yorkshire Fire Service said.
Head teacher Maria Williams said the main teaching areas had been saved and it was believed no student work had been lost.
She said because exams had finished there was a reduced number of pupils in school with only years seven to 10 and 12 due to be there.
Ms Williams said: "I cannot thank the fire service enough for working so hard through the night to save our school.
"We hope very much that we can get back into school and that teaching and learning can continue for our students as soon as possible."
At its height, firefighters from six stations across North and West Yorkshire tackled the blaze.
Rosemary Macklam, 24, a former student, said: "You could see the flames from about a mile away.
"It looked like the swimming pool and changing rooms were the worst hit."
North Yorkshire County Council said once the site had been handed back to the authority from the police and fire service, work would begin to resume teaching.
The council said the school's senior leaders were working out of the main reception area and asked that people stay away until further notice.