City fire officials are investigating the cause of a three-alarm fire in the Bronx early Monday morning.

The FDNY says the fire started around 6 a.m. on the top floor of a vacant home located at 2075 Anthony Avenue in Mount Hope.

Flames from the fire spread to an adjacent home.

Three families who were in the second home were evacuated.

"The building was coming apart as a result of the fire, we had electrical wires that were affected and live wires that were falling and sparking around operating members.," said one firefighter at the scene.

Nearly 140 firefighters responded to the fire.

Two of them were injured.