The shooting began around 10:30 a.m. Monday, when a caller phoned the emergency dispatch about a woman bleeding on the ground outside Oikos University, police said.

The suspected gunman, named by authorities as 43-year-old former student One L. Goh, stood up in the middle of a nursing lecture and began shooting at his classmates. He then continued his attack throughout the building, where about 35 students were trapped.

Paul Singh, whose sister was wounded in the shooting, told Reuters that the gunman told his fellow students: “Get in line and I’m going to kill you all.”

Pastor Jong Kim, founder of the small Korean university, said the shooter was previously a nursing student at Oikos but was either expelled or dropped out on his own.

Goh was arrested a few hours after the shooting at a nearby Safeway supermarket. Oakland Police Chief Howard Jordan said Goh allegedly hijacked a car to get to the shopping center.

He then confessed to a Safeway security guard, who had noticed him acting suspiciously, that he had just shot several people and wanted to talk to authorities, several witnesses told KGO-TV.

The gunman did not appear to target specific victims, and his motive remains unclear. Investigators said the suspect, Goh, was a neutralised U.S. citizen from Korea and did not have a criminal past.

Five people died at the scene of the shooting, two more died in hospital and the three injured victims were not in serious critical condition, police said.

“Today was an unprecedented tragedy, shocking and senseless,” Jordan said Monday night.

“No words can express the gravity of this incident.”

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