Crews with the Thunder Bay Fire Service responded to a house fire on Merrill Street on the city's north side this weekend.

No one in the was hurt, but the home suffered "heavy fire and smoke damage," according to a release.

It happened at around 3 a.m. Monday. That's when witnesses reported smoke and flames coming from the home's windows.

When crews arrived, the fire had engulfed much of the basement and extended through a main floor bedroom and bathroom. All occupants were able to escape the home, according to the Fire Service.

The cause of the fire is under investigation.