A headteacher has pledged to open her school as usual on Monday - despite damage from an arson attack.
Firefighters were called to RL Hughes Primary School in Ashton on Friday night after a shed was set alight in the nursery outdoor play area.
The blaze spread to the main building and badly damaged a classroom used by year five pupils.
Wigan Council has confirmed the classroom needs "significant repair" but said the school will open as normal on Monday.
Children will be taught in another classroom and kept away from the damaged area.
Headteacher Monica Middlehurst said: “We are very upset that such a reckless act has been carried out on our school which will result in a significant amount of cost and time to repair.
“However, we are determined that the children and their education will not be adversely affected and we are working hard to have the damaged classroom repaired as quickly as possible.
“We have contacted parents to inform them that the school will open as normal on Monday and will continue to work in partnership with the council, police and fire brigade.
"I would especially like to thank the fire brigade for their speedy response which prevented the damage being much more widespread."
An investigation has been launched into the fire, which is thought to have been started by a group of teenagers who climbed over a fence.
Firefighters from Wigan and Hindley were called to the Mayfield Street school on Friday night and spent three hours working to save the building.
Mark Anderson, watch manager at Hindley fire station, said: "We received it at just after 10.30pm to say the school was on fire.
"On arrival it was a shed which was attached to the school, which had then spread to the school and damaged a classroom.
"The classroom is now not usable."
Mike Fairhurst, crew commander at Wigan fire station, said: "We did quite well because we got a good hit on the fire straight away and stopped it spreading into the rest of the school.
"The outside of the school was wooden-clad and the whole of the outside of that building was affected. It affected the roof and we had to strip away inside the classroom as well.
"We did a really good job because it was just the classroom that it ended up affecting, not the rest of the school."
He added: "It's a shame for the kids just before Christmas."
Firefighters in breathing apparatus used hose reels, thermal imaging cameras and water jets to tackle the fire.
Group manager Ben Levy said: “The crew were faced with a significant fire when they arrived and immediately requested more fire engines to help them bring the blaze under control
“The shed was completely destroyed by fire, but the crew did a fantastic job to prevent it from spreading to the main school building.
“Some of the classrooms did sustain damage but firefighters acted really quickly to salvage electrical items like smart boards to ensure they weren’t damaged by the fire.
“Officers from Greater Manchester Police attended this incident along with us and we believe this fire was caused by arsonists."
Police are now investigating what happened and are treating the blaze as arson.
They are asking anyone with information about what happened to contact them - an appeal which has been echoed by both the fire service and the council.
CCTV footage from the school is being examined as part of the investigation.
A police spokesman said: "We are treating it as suspicious.
"The description of the offenders is aged 14 to 17, about seven of them, all men.
"Any information can be passed on via 101, quoting log number 2626 of December 9."