A two-alarm fire that burned two buildings in Noe Valley on Monday afternoon was extinguished in about 50 minutes, a Fire Department spokeswoman said.

The blaze was reported about 2:35 p.m. on the top floor of a three-story building at 276 Jersey St., then spread to a second building, Fire Department Lt. Mindy Talmadge said.

Firefighters responded and extinguished the fire by 3:22 p.m., Talmadge said.

The blaze affected four units at the two buildings. The American Red Cross is assisting the displaced residents, Talmadge said.

She said the fire caused some electrical wires to fall, prompting PG&E to shut off power to the lines.

No one was injured in the blaze, the cause of which remains under investigation, she said.