SOMERVILLE — A two-alarm fire heavily damaged a three-decker on Sydney Street in Somerville late Tuesday night, Fire Chief Patrick J. Sullivan III said.
About 35 firefighters responded to the blaze at 31 Sydney St. that was reported at about 10:40 p.m., Sullivan said at the scene.
The fire swept through the third floor apartment and roof. Windows were blown out of the home located on a heavily residential street in East Somerville.
He estimated damages of at least $500,000. The cause remains under investigation, he said.
No one was believed to be injured in the fire, Sullivan said.
It was unclear how many people were displaced, but all who live in the units were accounted for, Sullivan said.
The Red Cross wrote on Twitter that it was responding to assist residents impacted by the fire.
Traffic was closed on Sydney Street before the fire was knocked down around 11:45 p.m.
Cambridge fire reported on Twitter that it had provided coverage for Somerville stations while firefighters responded to the scene.
Globe correspondent Jake Johnson contributed to this report. Danny McDonald can be reached at firstname.lastname@example.org.