HAPPY VALLEY, Ore. - A gunman opened fire inside an Oregon shopping mall on Tuesday in the middle of the busy Christmas season, killing at least two people and terrorizing holiday shoppers be f ore he shot himself to death, police said .

The afternoon shooting rampage at the crowded shopping center in the Portland suburb of Happy Valley touched off a panic inside the mall, with shoppers streaming out as police and fire crews arrived on the scene.

"I can confirm that we believe at this point that there was one and only one shooter involved and that that shooter is deceased," Clackamas County Sheriff's spokesman Lieutenant James Rhodes told a press briefing.

"In addition to that, we have at least one patient who was taken from the mall with a traumatic injury and at least two that were deceased in addition to the shooter," he added.

Rhodes said later that the suspect died from a self-inflicted gunshot wound and that police had not fired a single shot inside the mall.

High school student Hannah Baggs, 14, told the Oregonian newspaper that she got a close look at the gunman before he entered the mall and opened fire.

" He was, like, 10 feet away from us, wearing a white mask and carrying something heavy with both hands," Baggs said in remarks carried on the newspaper's website. "He went running into the store."

Police evacuated terrified shoppers, who were reported by local media and via Twitter to have hidden in the back rooms of shops as gunshots rang out in the mall.

The Oregonian also said on its website that the gunman had used a semi-automatic rifle and may have also been wearing body armor, but police did not immediately confirm that. The paper said the shooting occurred near the mall's food court.

"All of a sudden I heard something similar to a .22 popping, probably eight times, and people dropping everywhere, people screaming," witness Christina Fisher said in an interview aired on CNN. "It was chaos."

Oregonian sports reporter John Canzano, who said he was at the mall when the shooting began, tweeted that "panicked people are running from the mall" and later urged his followers simply to "pray."

Police and SWAT teams established a perimeter around the scene and worked to evacuate the mall as they searched for the gunman. Video footage from inside the mall, aired on CNN, showed shoppers heading toward exits with their arms raised above their heads.

The identities of the dead and wounded were not immediately released. A spokeswoman for the mall said she had no immediate information and directed calls to law enforcement authorities.

The incident marked the latest in a string of shooting rampages this year that included the killing of 12 people and wounding of 58 others at a midnight screening of "The Dark Knight Rises" in Colorado.