Authorities were sent to a home around 10:44 p.m. on a shooting report.
Paramedics declared a mass casualty incident, reporting 12 patients.
Three men in their 20s were dead at the scene and nine patients were transported to local hospitals, according to the Long Beach Fire Department.
Paramedics were seen treating the wounded in a yard next to a nail salon before transporting them to nearby hospitals.
At 10:44 pm, @lbfirefighters responded to shooting at a residence on the 2700 block of 7th Street. An MCI was declared with a total of 12 patients. 3 confirmed fatalities (adult males) 9 patients transported to local area hospitals. 5 immediate & 4 delayed. PIO onscene. pic.twitter.com/k8txxNqZfL— Long Beach Fire (CA) (@LBFD) October 30, 2019
At least three bodies were visible on the ground.
Jake Heflin with the LBFD said the shooting took place at a Halloween party, and all patients transported may have been hit by gunfire.
Heflin added that the suspects remain at large, although the exact number of suspects involved was not clear and a description was not available.
It appears the shooting took place outdoors. Multiple shell casings were seen in the alley behind the home.