Three people were killed and 11 others injured in a fire that sent residents jumping to safety from a three-story apartment building in San Francisco. Residents at the 12-unit building leapt onto nearby rooftops to flee the flames early on Thursday, fire officials said.

"First I heard people jumping off the balcony into our courtyard," neighbour Dave Ciaccio said. "Then I looked out and I saw people running from one rooftop to the next rooftop to the next, trying to escape."

At least 20 of the building's residents were Mexican, said Alfonso de Maria Campos, the General Consul of Mexico, who went to the scene on Thursday morning. The bodies of three people were found inside the charred building. Five others and six firefighters were hurt, Fire Chief Joanne Hayes-White said.

Four people who jumped out of windows were taken to hospitals, including one with multiple leg fractures who was in critical condition, fire officials said. "There were three stories of flames and a lot of heat," said firefighter Ken Smith. "A lot of crews took a real big beating and sustained some injuries as a result of the fire."

Fire officials were investigating the cause of the blaze that was brought under control soon after firefighters arrived.