BERKELEY (CBS SF) — Firefighters extinguished a two-alarm fire at a commercial building in downtown Berkeley Saturday afternoon, a deputy fire chief said.

Firefighters responded at 3:43 p.m. and found a fire burning in a retail structure with two addresses, 2111 and 2115 University Ave. The fire had started outside of the back of the building and then spread inside, deputy fire chief Donna McCracken said.

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Crews eventually extinguished the fire by about 5:30 p.m. No civilians were injured but a firefighter suffered a minor arm injury, McCracken said.

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A nearby apartment building was evacuated during the fire response. The residents remained outside the building as of 6:45 p.m. but were expected to have been allowed back in later in the day.

The cause of the fire remains under investigation and a damage estimate was not immediately available, she said.

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