A number of children had to be led to safety after arsonists set fire to part of a West Yorkshire sports stadium on Wednesday night.
Police say the track seating area at Thornes Park Stadium in Wakefield was deliberately set alight at about 7:25pm on Wednesday evening, with the blaze spreading to a nearby building where a children's sports club event was being held.
Fire crews were called immediately after the blaze started, with the fire spreading to an overhanging section of a roof of a nearby building full of children attending the sports club.
Three crews attended the scene from Wakefield, Ossett and Dewsbury and used two hose reels, two breathing apparatus and a high-powered fan to clear smoke from the building.
West Yorkshire Police described the incident as a "deplorable case of anti-social behaviour" and appealed for anyone with any information to come forward.
Nobody is believed to have been hurt in the incident.