Updated 3:10pm: Three high school students are fighting for their lives, after suffering gunshot wounds to their heads in a school shooting in the US.

A fourth student has non-life threatening injuries after the shooting, at a high school in the state of Washington.

Providence Regional Medical Centre's Dr Joanne Roberts says the hospital is working to verify the identities of their patients so parents can be told.

"They are all either in the operating room or on their way up to the ICU.

"All received surgery."

Police have confirmed one student died in the attack, and the shooter is dead from a self-inflicted injury.

Police commander Rob Lamoureux says officers are still carrying out a search of the whole school before giving the all-clear.

"I don't know where our officers are at at this point.

"They are clearing the building.

"We are confident that there was only one shooter and that the shooter is deceased but we do need to clear each building and make sure that's the case."