The incident took place at the Gable House Bowl, a bowling alley and arcade that also offers laser tag, a local ABC affiliate reported.
"Reports of shots fired with multiple victims down. T P D is on scene. Investigation is ongoing. Please stay away from the area," Torrance Police Department (TPD) said on Twitter, without giving further details about the number or condition of those involved.
Gable House Bowl patron Jesus Perez told the Los Angeles Times that he heard about four gunshots.
"We just ran right into the bar and took cover. All we heard was just, like two people got shot," he told the newspaper.Torrance is about 25 miles (40 km) south of Los Angeles.