By Catherine E. Shoichet and Michael Martinez, CNN
updated 8:24 PM EST, Tue December 11, 2012

(CNN) -- Panicked customers ran for cover when a gunman opened fire at a mall outside Portland, Oregon, Tuesday.

Authorities believe at least one person was killed in the shooting at the Clackamas Town Center mall, said James Rhodes of the Clackamas County Sheriff's Office.

The shooter "has been neutralized," Rhodes said, and there is no longer active shooting at the mall. He declined to comment when asked whether the gunman had been killed.