Fire crews are still on the scene of an early morning structure fire in Kelowna's City Park.

At 4:36 a.m. Sunday, the Kelowna Fire Department was called out to a report of a fire in City Park.

"Crews arrived and saw that it was a little more than a small fire and upgraded our response to full structure," says Kelowna Fire Department Assistant Chief Thomas Doherty.

With flames from the City Park Pavilion building reportedly reaching 50 feet into the morning sky, firefighters were forced to take a defensive position.

The building housed the City of Kelowna Design and Construction Services, a concession stand and public washrooms.

"It looks like a total loss, and depending on what the City had in there the dollar loss could be quite high," says Doherty.

The building sustained significant damage throughout.

"It's basically a write-off."

"At this point the fire looks like it started in the lower level of the building," says Doherty, adding that it is believed to have started in or near the concession stand.

No injuries have been reported at this time and the cause of the fire is under investigation.