Officers were responding to an active shooter in the northeast of the city.
Three victims were in an “extremely critical” condition, a spokesman for the San Bernardino Police Department said.
Captain Richard Lawhead said multiple weapons were fired.
He said none of the victims had died.
Detectives do not have a suspect in custody or a motive for the shooting.
No weapons were recovered from the scene, Mr Lawhead said.
#UPDATE: Police say a total of 10 people were shot on Lynwood Drive in #SanBernardino. 3 people are in “extremely critical” condition but there are no fatalities. Police say a group of people were playing dice in a common area of the complex when the shooting happened. #CBSLA pic.twitter.com/J0S82iu0kg
— Mike Rogers (@MikeRogersTV) September 3, 2018
Photos from the scene showed a massive police presence at East Lynwood Drive and nearby roads have been closed.
Alysa Marie, who lives near the complex, told CNN she heard 15-20 gunshots.
“My brother-in-law could hear bullets flying past our house, he was outside at the time of the shooting,” she said.
San Bernardino is located around 60 miles (96km) to the east of Los Angeles.
The shooting took place a week after a gunman shot nine people and killed two competitors at a video game tournament in Jacksonville, Florida.
Read on Yahoo! News