The gunman who opened fire on a group of students outside a Portland high school is a suspected gang member, police said.
A 16-year-old girl is in a critical condition while the condition of two boys, aged 17 and 20, is serious. A fourth woman, aged 19, was grazed by a bullet but did not need hospital treatment.
Police Sergeant Pete Simpson said preliminary information suggests the shooter has gang ties.
This is the second school shooting in Portland this year.
In June a 15-year-old shot another boy in a locker room at Reynolds High School before turning the gun on himself.
Two boys and a girl were injured in a shooting outside their high school in Portland, Oregon, police said.
The victims are believed to have been students at Rosemary High School, which serves 190 students who have dropped out or been expelled from mainstream schools.
The shooting is said to have taken place at noon outside the school - the shooter fled the scene and the victims ran inside the school to call for help.
Parents were summoned and a nearby high school and community college were put on lockdown.
Police said there is a possibility the shooting is gang-related.
US police said the shooter has left the scene of the high school where three victims were injured. Police said the school is now secure and safe.
Police in Portland, Oregon are responding to reports of a shooting outside a High School. Three people are believed to have been injured, and have been transported to hospital. They fled into the school after the shots were fired, police said.
Police have arrived at the scene of a shooting near a high school in the US state of Oregon.
The authorities have said there are at least two victims at the Rosemary Anderson High School in the city of Portland, Associated Press reports.
Police said there are at least two victims in a shooting in a school in Portland, Oregon in the US.
Police did not say whether the victims were shot or not or give details on their condition.
The school, Rosemary Anderson High School is an alternative school for students who have been expelled or dropped out of mainstream education.
Parents have been summoned to the school.
Nine people have been killed and at least 20 others injured after a bus travelling from Las Vegas to Canada crashed in north east Oregon.
The charter bus skidded off an icy motorway and crashed down an embankment, according to police. State police spokesman Gregg Hastings said:
Police said the names of the dead and wounded would not be released until next of kin were notified, which could take several days because many were believed to be from out of the country.
Police have confirmed that five people have been killed and about 20 have been injured in a tour bus crash on icy Oregon interstate highway.