Oregon shooting: At least 3 shot outside Rosemary Anderson High School in Portland

Vulnerable students including those who have dropped out of high school, are homeless, or otherwise at-risk attend the school

A screenshot from the Sky News coverage of the Oregon shooting (Sky News, via YouTube)

Two boys and a girl have been shot at a street corner outside a school in Portland, Oregon, say officials.

The Fire Department said the victims had been taken to hospital, as police were searching for the assailant who fled from the Rosemary Anderson High School in the northwestern city.

The three victims, believed to be students, then ran back to the school for help, said Police Sergeant Pete Simpson.

The Portland Oregonian newspaper reported that a 17-year-old was shot in the back and that a female student was struck in the chest. There was no immediate information on the third victim.

All three victims were "conscious and breathing" as they were rushed to a local hospital, said the Portland Police.

Police officers reported the shooting after midday on Friday, and believe it may have been gang-related.

The facility in Portland accommodates 190 students who have dropped out of high school and other at-risk or homeless students, according to its website.

Meanwhile, Jefferson High School and Portland Community College were also both placed on lockdown following the shooting, and traffic was being diverted from the area, police said.

Students’ parents have been summoned, and were directed to go to a staging area several blocks from the school.

Aly Wright, who works at the Coffeehouse Five coffeehouse near the school, said her customers heard several gunshots, followed by the quick arrival of police.

"This whole block is on lockdown," she said.

The incident follows a shooting in Portland in June, where a first year student killed one student and before fatally turning the gun on himself.

Jared Padgett, 15, opened fire after arriving at his high school east of Portland heavily armed.

He killed 14-year-old Emilio Hoffman in the boy's locker room and another bullet grazed a physical education teacher. When confronted by officers, Padgett went into a bathroom and died from a self-inflicted gunshot, police said.

Additional reporting by AP