Three men have been killed and four wounded in a shooting in the US state of California after a late-night fight at a bowling alley.

The Torrance Police Department said officers responded to calls of "shots fired" at the Gable House Bowl in Torrance, a town about 40km south of Los Angeles, shortly before midnight on Friday

Multiple victims were found with gunshot wounds inside the gaming venue, which offers bowling, laser tag and an arcade.

Police said three men died at the scene and four male victims were injured, two of whom were transported to a hospital for unknown injuries while the other two injured sought medical treatment on their own.

"Investigators are currently conducting a follow-up investigation, and are working to identify the suspect(s) involved," the department said in a statement.

Authorities have not released details about what led to the shooting, but witnesses said it stemmed from a fight between two large groups of people at the bowling alley.

'Complete chaos'

Wes Hamad, a 29-year-old Torrance resident, was at the bowling alley with his 13-year-old niece and cousin when he saw a "huge fight" break out.

Hamad told the Associated Press news agency that the brawl, which lasted about five minutes, blocked the entrance of Gable House Bowl and devolved into "complete chaos".

"I grabbed my niece and started running toward the far end of the bowling alley," Hamad said. "As we were running, we heard 15 shots."

As he was leaving, Hamad said he saw a woman weeping over a man who had multiple gunshot wounds to his head and neck.

Damone Thomas was in the karaoke section of the venue, a regular stop for him and his friends after work on Fridays, when people ran in saying there was a shooting.

The 30-year-old Los Angeles resident said his friend flipped over one of the tables to shield them as they heard gunshots.

Thomas told the AP he didn't feel scared because he was "just trying to survive". But when he was driving back home, he said he realised how traumatic the situation had been and he hasn't been able to fall asleep.

"Closing my eyes, all I can see is the women against the wall crying, not knowing what to do," he said.

The US has long dealt with the issue of mass shootings. In the first four days of 2019, there have been five mass shootings that resulted in five deaths, according to the Gun Violence Archive, a group that tracks such incidents.

Both Thomas and Hamad said they had never witnessed any violence at Gable House Bowl in the past, but Hamad said he had stopped going for a while because he heard someone with a gun was recently seen there.

"I definitely won't be going back any more," he added.

According to health authorities, nearly 40,000 people died in the US as a result of firearms in 2017 - a figure that includes suicides.