UPDATE: Jake Heflin with the Long Beach Fire Department 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.

LONG BEACH, Calif. (KABC) -- Three men were killed and nine people were wounded in a shooting Tuesday night at a home in Long Beach.

Authorities were sent to a home in the 2700 block of 7th Street, near Temple Avenue, at 10:44 p.m. on a shooting report.

Paramedics declared a mass casualty incident, reporting 12 patients. Three men 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 least three bodies were visible on the ground.

It appears the shooting took place outdoors. Multiple shell casings were seen in the alley behind the home.

No description of a suspect was immediately available or information about whether the person or persons were in custody.