Fire crews put out a blaze in an apartment in northwest Calgary on Thursday afternoon. (CBC)

Calgary fire crews were busy at an apartment fire on Thursday afternoon.

Around 4 p.m. MT, a fire broke out on the fifth floor of an apartment building in the 300 block of Tenth Street N.W.

Everyone left the building safety and nobody was injured.

Fire crews extinguished the fire shortly after arriving.

The cause of the fire is unknown.