The suspected shooter is also dead, the Multnomah County Sheriff’s Office said. It was not immediately clear how the shooter died.
There was only one shooter involved in the incident, police said.
About an hour after the shooting, Oregon State Police said the area was secure and the situation was contained.
The shooting happened at about 8 a.m. (11 a.m. ET) at Reynolds High School in Troutdale, about 12 miles east of Portland, said Sue Strickland of the Troutdale Police Department.
A semi-automatic weapon was involved in the shooting, she said.
“Today is a very tragic day for the city of Troutdale and Reynolds School District,” Troutdale Police Chief Scott Anderson said.
Classes were in session at the time, Strickland said. It wasn’t clear how many people were injured, and details about what led to the shooting weren’t immediately available.
A couple of SWAT teams responded, Strickland said.
Anxious parents waited for news that their children were safe. One couple, Craig Tuholski and Tawnjia Reimer, were talking with CNN affiliate KGW, about how agonizing the wait for news was, when Tuholski’s cellphone rang.
“Is that Chris?” Reimer asked before letting out a sigh of relief. “Oh, thank God.”
“That’s what we were waiting for,” Tuholski said after hanging up.
Troutdale has a population of about 16,400, according to the Census Bureau.
“My thoughts and prayers are with students, staff and the Reynolds High School community during this difficult time,” Oregon Gov. John Kitzhaber said via Twitter.