One person was killed and three others were wounded in a shooting Tuesday near two polling locations in Azusa, California.

Los Angeles County Fire Inspector Gustavo Medina said one person died after being taken to a hospital.

The Los Angeles County Sheriff’s Department is assisting the Azusa Police Department with the officer-involved shooting, Sgt. Vincent Plair told CNN.

An LA County Sheriff’s Department helicopter took at least two shooting victims to a hospital.

The polling centers have been “impacted,” authorities said.

Two voters who were inside the Memorial Park North Recreation Center when the shooting occurred spoke to CNN on the condition of anonymity. The shots were not fired inside the polling station, witnesses said.

One voter says he was inside when he heard a bunch of shots ring out and people from outside starting to run in before officials locked the doors. He told CNN a “massive shooting is happening and the police have told us to stay indoors. We are currently on lock down.”

Another voter told CNN she heard the shots ring out.

“At first, I thought it was construction but people came running into the room saying they see a guy with a bulletproof vest and a white shirt. As of right now, they just have us in the voting room and are trying to keep us calm,” she said.

Officials were not allowing anyone to leave the building but people were still being allowed to vote while they waited, the woman said.

Pictures sent to CNN from inside the polling station showed many people inside, including a group of children who were in the building when the shots were heard.

The woman estimated about 30 people remained inside the locked-down polling location. About 15-20 children were evacuated from a gym inside the recreation center where people were voting, she said.

“Voters should avoid the area and, if necessary, cast a ballot at an alternate polling location,” LA County Registrar Dean Logan tweeted.

Azusa is located roughly 30 miles east of Los Angeles.