Police allege a small fire at a Regina high school was deliberately set by two children.

An exercise mat caught fire in a hallway of F.W. Johnson Collegiate around 4 p.m. Thursday.

Classes were done for the day, but some students and staff had to be evacuated from the building. No injuries were reported.

Police say charges won't be laid against the two children, as they are under the age of 12.

The case has been referred to social services, and the Regina fire department plans to educate the two youths about fire safety.

Damage is estimated at $150,000.