Police have said two people are dead following a shooting at a high school in Washington state. The attacker is among the dead.

It is not known how the attacker died in the incident at Marysville-Pilchuck High School in Washington state, but there are reports he took his own life.

Three young people in a "very critical condition" were admitted to Providence Regional Medical Center in Everett, said its chief medical officer, Joanne Roberts.

She said one other patient, less critically injured, was sent to Harborview Medical Center in Seattle.

One student told CNN that the attacker, who was said to have been a victim of bullying, had a "blank stare" as he stood up the cafeteria and began shooting.

Another student, named only as Alex, told KIRO TV he was in the cafeteria when the attack occurred.

"I was eating," he said. "I heard four gunshots and it was behind me. I saw a gun pointed at a table ... then I ran out of the exit."

TV footage showed students being evacuated from the school, which has about 2,500 enrolled.

Armed police were conducting room-to-room searches with guns drawn, leaving tape to mark the doors of areas already cleared, reports the Seattle Times.

An FBI spokesperson in Seattle, Ayn Dietrich, said the agency had sent personnel to the scene 30 miles (48km) north of Seattle.

Another shooting occurred in the state in June at Seattle Pacific University, where a gunman killed a student and wounded two others.

The same month a teenager shot and killed another student and injured a teacher before taking his own life at a high school in the neighbouring state of Oregon.