By WCCO-TV Staff

MINNEAPOLIS (WCCO) — Multiple crews have responded to a residential fire in North Minneapolis Thursday morning.

The fire, according to crews, was at a 2 1/2 story duplex on the 3700 block of Knox Avenue North. It was reported around 11 a.m. and upon arrival, crews found heavy fire showing from the upstairs level of the building.

It was reported as a two-alarm fire.

Crews opened up roof vents to allow for vertical ventilation.

The Minneapolis Fire Department described heavy amounts of fire, traveling in the walls.

All residents evacuated the building. Red Cross assistance was called for seven adults, five cats, and two dogs.

One firefighter was examined for over-exertion at the scene, but was able to return to work soon after.

The cause of the fire is under investigation.