There were some tense moments Tuesday morning at King George Elementary School in Saskatoon, seen here in a 2009 Google Street View image. ((Google))

Fire broke out at a Saskatoon elementary school on Tuesday, but a fast-acting principal extinguished it before anybody was hurt.

It happened on the second floor of King George Elementary School on the city's west side at around 9:30 a.m. CST.

More than 150 students and staff had to be evacuated from the building.

The principal grabbed a fire extinquisher and put out the blaze before firefighters arrived.

It appears it was deliberately set, fire officials said.

"We believe it was caused by someone, and that's under investigation right now," fire department spokesman Terry Novakovski said.

More information should be available at the end of the day, Novakovski said.