At least six families are homeless after a fire started at their Yonkers apartment building, but they might be able to return home within several days.

The fire broke out at about 8 p.m. Tuesday on the roof of 110 School St. Tenants say they knocked on other doors to alert people after a neighbor first spotted the flames from outside.

"I saw flames coming out from the corner of the building," says Jose Martinez, who owns an auto-repair shop across the street. He ran into the building with the fire. "I called 911. The other guy and me, we went up there and called the people to come downstairs."

No one was injured. 

Authorities say it took 40 firefighters about an hour to extinguish the flames from above on ladders. The cause of the fire is under investigation, but a crew had been working on the building's roof earlier.

The Red Cross is assisting the six families that are now homeless. The building owner says the property damage, which was mostly caused by water, isn't that bad and that tenants might be back home within days.