Detective Sergeant Mark James, of the Hamilton police crime investigation unit, said the male youths - aged 12 years old and 15 years old - had handed themselves in to the Hamilton police station.

He said they had been interviewed and it was expected they would receive cautions.

"They were playing with matches and lighters, ignited flammable material inside the shed which spread and the boys couldn't put it out," he said.

"We would like to thank the public for their assistance in providing photos and videos taken before the police and Country Fire Authority officers arrived at the scene," he said.

Emergency services were called to the shed fire at 4.45pm on Monday.

The shed - about 10 metres wide and 200 metres long - was partially destroyed in a fire which started at the eastern end of the building.

Detective Sergeant James is currently on the way to investigate the circumstances surrounding a car being found burnt out on Thursday morning at Pilleau Street, Coleraine.