Media playback is unsupported on your device Media caption Police searched the mall for anyone left injured or hidden inside a store, as the BBC's Alastair Leithead reports

A gunman has opened fire at a shopping mall near the city of Portland, Oregon, killing two people and himself.

One other person was seriously injured at the Clackamas Shopping Center and was taken to hospital, Lt James Rhodes of Clackamas County Police said.

The gunman killed himself and police who arrived at the scene did not fire, say the authorities.

Dozens of police and emergency medical teams searched the premises for shoppers hiding inside, Lt Rhodes said.

Police say the gunman was a man in his 20s, but they have not named him.

The third victim, Kristina Shevchenko, remains in a serious condition at a Portland hospital.

Mission of murder

Clackamas County Sheriff Craig Roberts said it appeared to have been an entirely random attack.

Image caption Darkness fell on the shopping centre after the shooting

The gunman apparently targeted "anyone who was in his line of sight", Clackamas County Sheriff Craig Roberts told NBC's Today show.

"It was very apparent that he had a mission set forth to really take the lives of people in that mall," he added.

The shooting began at about 15:30 PST (23:30 GMT) in Clackamas, a suburban town on the southern fringe of Portland, in the middle of the Christmas shopping season.

Witnesses said the gunman opened fire several times while on the second floor of the shopping centre, near the food court and Macy's department store.

Some of those present said that as he opened fire, the attacker called out: "I am the shooter."

Multiple witnesses reported to local media that the gunman was wearing a mask and brandishing an assault-style rifle.

Taylor Gibson, an employee at Build-a-Bear, said when she first heard the shots, she and others rushed customers to the back room and closed the store's front gate.

"That gate takes 30 to 45 seconds to close," she told the Oregonian. "Honestly, as I was shutting that gate I was waiting for that person to walk up the hallway and shoot me."

Evan Walters, who worked at the mall and was locked inside a store, told local broadcaster KATU he saw two people who had been killed. He and other store employees placed sheets over the bodies.

The shopping centre Santa, Brance Wilson, told the Associated Press news agency how he dived for cover as gunfire rang out.

"I heard two shots and got out of the chair," said Mr Wilson, 68. "I thought a red suit was a pretty good target."

In a statement, Oregon governor John Kitzhaber said: "my thoughts and prayers are with the victims and their families... I have directed State Police to make any and all necessary resources available to local law enforcement".