One person is in critical condition and has potentially life-threatening injuries, Lt. Rich Chatman said during a news conference.
Five others were admitted to hospital with injuries from which they had to recover, he said. An indefinite number of other people were injured but did not need to go to hospital.
The crime scene spans more than a dozen blocks in southeast Portland, on both roads and sidewalks.
“As you can imagine, there was a lot of chaos going on,” Chatman said.
Portland police officer Derek Carmon said the vehicle, a Honda Element, eventually crashed, and witnesses “just” corrected “and restrained the suspect until police arrived.
Police did not release any information about the identity or motive of the suspect.
Vehicles were also hit during the incident, according to a news release issued by the police station earlier Monday.
Calls to 911 began shortly after 1 p.m. PT, police said.
Police said it would take hours to clear up debris and gather evidence about the wide-ranging crime scene. They ask local residents to provide them with additional evidence they encounter.
“And a video,” Carmon said. “Video is great.”