One witness at the Clackamas Town Center told television station KATU at least two people were shot, and he saw sheets put over them.
Another witness told the station she saw people screaming and parents grabbing their children as they fled the mall.
That witness said the gunman had a rifle and was wearing a camouflage outfit and a mask.
Another witness said ambulances were arriving at the scene.
Entrances to the mall have been blocked off.
No further details were immediately available from the Clackamas County sheriff's office.
Gunmen Ran In the Mall Yelling, "I Am The Shooter!" One person says more than 60 shots fired!
PORTLAND, Ore. — A gunman opened fire in a suburban Portland shopping mall Tuesday, killing two people and wounding another as people were doing their Christmas shopping, authorities said.
Witnesses described a scene of chaos and disbelief as a gunman wearing some sort of camouflage outfit and a white mask shot an initial burst of fire and then more rounds at Clackamas Town Center. Shoppers tried to find safe areas as teams of police officers began entering the mall to find the shooter.
Clackamas County sheriff's Lt. James Rhodes said later that the gunman was dead, but he wouldn't say how he died or provide any details about him.
Authorities were going store-to-store to secure the scene and to escort hiding shoppers outside, but Rhodes said there was no indication that there was more than one shooter.
Austin Patty, 20, who works at Macy's, said he saw a man in a white mask carrying a rifle and wearing a bulletproof vest.
He heard the gunman say "I am the shooter," as if announcing himself, Patty said. He then fired several shots paced seconds apart.
A series of rapid-fire shots in short succession followed. Patty said he ducked to the ground, then ran.
His Macy's co-worker, Pam Moore, told The Associated Press the gunman was short, with dark hair, dressed in camouflage. He had body armor and a rifle.
"I heard about 20 shots and everyone hit the ground," Moore said. "That's when we all just ran."
Shaun Wik, 20, from Fairview, said he was Christmas shopping with his girlfriend and opened a fortune cookie at the food court. Inside was written "live for today, remember yesterday, think of tomorrow."
As he read it, he heard three shots. He heard a man he believes was the gunman shout, "Get down!" but Wik and his girlfriend ran. He heard seven or eight more shots. He didn't turn around.
"If I had looked back, I might not be standing here," Wik said. "I might have been one of the ones who got hit."
Kira Rowland told KGW-TV that she was shopping at Macy's with her infant son when the shots started.
"All of a sudden you hear two shots, which sounded like balloons popping," Rowland told the station. "Everybody got on the ground. I grabbed the baby from the stroller and got on the ground."
Rowland said she heard people screaming and crying.
"I put the baby back in the stroller and ran like hell," Rowland said. "It was awful. It was shots after shots after shots like a massacre.
"It was just awful."
Holli Bautista, 28, said she was shopping in the Macy's for a Christmas dress for her daughter when she heard a two or three pops that sounded like firecrackers.
"I heard people running and screaming and saying `Get out, there's somebody shooting,'" she told the AP. "It was a scene of chaos."
She said hundreds of shoppers and mall employees started running, and she and dozens of other people were trying to escape through an exit in the department store.
Bautista said the Macy's opens into the food court area, where it was reported the shootings took place. Bautista said it sounded like the shots were coming from that direction.
Tiffany Turgetto and her husband of Gladstone had exited Macy's through the first floor when they heard the gunshots coming from the second floor of the mall.
"People in front of us people were dropping, finding covering," she told the AP. "People were yelling screaming and gasping, yelling to get out. The lady next to us, she threw a chair and started running. We couldn't run because the chair was there."
Turgetto and her husband and other people were able to quickly leave through a Barnes & Noble bookstore before the police arrived and locked down the mall.
"I had left my phone at home. I was telling people to call 911. Surprisingly, people are around me, no one was calling 911. I think people were in shock."
Hundreds of people ran or took cover during chaotic scenes as a gunman opened fire in an Oregon mall yesterday, killing 2 people before apparently taking his own life. "I heard two shots and got out of the chair. I thought a red suit was a pretty good target," the Portland-area mall's Santa tells the AP. Police say around 10,000 people were in the mall when the gunman, wearing a hockey mask and possibly body armor, opened fire. A security guard says he heard shots before a shout of "Everyone on the ground," the New York Times reports.
"I was by Santa Claus in front of Macy's when we heard, 'Pow. Pow. Pow,'" a World War II veteran who saw a crowd of terrified shoppers fleeing tells the Oregonian. "People screamed and ran. I saw Santa drop to the floor." Some shoppers and mall workers hid for hours while police made sure there was only one shooter. Police say they have tentatively identified a 22-year-old suspect but have not released a name or any information on a possible motive. A 15-year-old girl was seriously injured but police say the toll could have been much worse. Witnesses say the gunman's rifle jammed soon after the rampage began.