UPDATE: Two people are dead and three others injured after a shooting at a polling station in Azusa, California, local police confirmed.

Azusa police said one victim has been killed, while two are in critical condition and have been transported to a local hospital. Another is injured but not critical.

The gunman was found dead shortly after in a house when police opened fire.

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Police were hunting a suspect armed with a semi-automatic rifle believed to be male, Azusa police chief Stephan Hunt said in a press conference.

The department said the incident began at 2.02pm (local time), with reports of shots fired near Memorial Park in Azusa.

“We don’t know if the suspect is accounted for,” Chief Hunt said earlier.

“We have seven tactical teams at the location.

SWAT team moves in on a barricaded suspect after several people were shot at that location in Azusa. Photo: AAP

“We believe we have that area contained very well.

“It’s very early to tell what the motive is, but it appears to be concentrated on the residential side, not at the polling station.”

The confirmed shooting victims include two females and two males, but Police chief Hunt could not confirm names or provide further details of the deceased.

The Los Angeles Times said the victim killed was a man in his 70s.

Police responding to the report of gunshots came under fire themselves and were initially pinned down as they arrived on the scene, according to accounts from Azusa police.

Officers returned fire and surrounded a house where the shooter appeared to have originated.

Police originally thought the suspect was a woman carrying an assault rifle with “rapid-fire capability,” Police chief Hunt said.

The situation has transitioned from active to contained, according to the Azusa Police Twitter account.

Residents are being told to seek shelter and avoid the area.

Situation has transitioned from active to barricade/containment… All those near scene shelter in place all others stay out of the area

— Azusa Police (@AzusaPD) November 9, 2016

The Los Angeles County Registrar and Recorder’s office have issued warnings to avoid the polling at Memorial Park and Dalton Elementary School, and to cast their ballots at alternative sites.