Damage is estimated at $20,000 following a fire at an apartment building in Cambridge.

Fire crews were called to the Elliott Street building shortly before 6 p.m. Monday.

Firefighters found smoke coming from the building’s attic, and a small fire at the back of the building.

The fire is believed to be electrical in nature.

Residents in four of the building’s apartments are expected to be unable to stay in their homes until later this week.