One firefighter was injured as crews battled a fire in a three-storey Montreal apartment building on Wednesday morning.

Firefighters say the extent of the damage means the six-unit building will be a complete loss.

The fire started at around 8:30 a.m. in a building on Osborne Street near Bannantyne Avenue.

"The fire started in the back," said Montreal Fire Department chief of operations André Paquette. "As the firemen arrived, they saw a lot of smoke and flames coming out of the first and second stories."

The firefighter's injuries were minor.