A popular restaurant in Arnprior has been gutted after an early morning fire spread through the building Monday.

Tosh Steakhouse Arnprior

The fire at Tosh Steakhouse and Bar was first reported early Monday morning at 3:18 a.m. (CBC)

Fire crews were called to the Tosh Steakhouse and Bar on 39 Staye Court Drive at 3:18 a.m. after people reported seeing smoke come from the roof of the building.

About 20 volunteer firefighters attacked the blaze, but heavy flames inside the building forced them to retreat and work to put out the fire from outside.

John Okum, the fire chief for the Arnprior Volunteer Fire department, said the damage to the restaurant is extensive, and said the building is not salvageable.

"It's a shame to see this kind of loss," said Okum, himself a regular at the restaurant.

OPP constable Hayley Chaplin was also a regular at the restaurant.

"We've been coming here since it opened — it's been open several years now — and it is regularly frequented by me and my colleagues so it really is unfortunate," said Chaplin.

Haley Rooney and her husband opened the restaurant in 2008. She said she's devastated by the loss but said they are already talking about rebuilding.

The cause of the fire is still under investigation.