At least one person is dead and several people are wounded this evening after a masked shooter opened fire at Clackamas Town Center, a mall in suburban Portland, Ore.

Police said the shooter had been "neutralized," but would not say whether the person was alive or dead.

"This is no longer an active shooter," Clackamas County Sheriff's Office spokesman Lt. James Rhodes said. "I believe the shooter has been neutralized and we are securing the mall, securing the scene and treating the wounded."

There was not an exact count of those killed or wounded, he said.

"We believe there's at least one deceased and maybe more," he said. "We know there are multiple wounded. Lifeline has landed to treat at least one of those wounded and we're set up to treat them as we find them as we search the mall."

Hundreds of people were evacuated from the busy mall full of holiday shoppers after the shooting began at around 3:30 p.m. PT.

Witnesses described seeing a gunman who looked like a teenager with a white hockey mask, wearing what was believed to be a black, bulletproof vest and carrying an assault rifle.

The person entered the mall through a Macy's store, ran through the upper level of Macy's and opened fire near the mall food court, firing multiple shots, one right after another, with what is believed to be a black, semiautomatic rifle, according to witness reports.

Witnesses described the shooter as being on a mission and determined, looking straight ahead.

Those interviewed said that Macy's shoppers and store employees huddled in a dressing room to avoid being found.

Evan Walters told ABC News Radio that he was locked in a store for his safety and he saw two people shot and heard multiple gunshots.