Photo: The Canadian Press. All rights reserved.

A police officer arrives at an apartment building in Vancouver, B.C., on Friday February 1, 2013, where seven people were stabbed by a man Thursday night. THE CANADIAN PRESS/Darryl Dyck

Residents of a Vancouver apartment building, alerted by shouting and screams, locked their doors as a man stabbed people in what police believe was a completely random attack.

Seven residents and one police officer were injured in the highrise building in the city's West End during the attack Thursday night.

Police said it appeared a male suspect, who was not a resident of the building, ran through the hallways slashing residents who police believe had no connection to him.

"He was in the building before this started. They're looking today at why he was in there," said Vancouver Police Sgt. Randy Fincham.

"It was something that happened in the building where he started this rampage and went floor to floor in the building and committed these random acts of violence against people that were already in the halls."

It is a "fairly significant crime scene and a lot of evidence to gather," Fincham said, adding that investigators are looking at whether mental health issues, drugs or alcohol may have played a role in the attack.

The suspect's name was not released.

A resident of the building said he heard screaming shortly before 7 p.m. a few floors below his suite.

"I got out of my apartment to check what was going on in the courtyard and there was definitely a commotion. At this point we didn't really know the extent of the attack," said the man, who did not want his name published.

Police arrived and blocked off all the entrances, he said.

"(We) saw five people taken away on stretchers," he said. "I think at that point, when we saw them, it really hit us that this was serious."

There are children living on the ground floor, and he said he was relieved to find out none of them were harmed.

The 33-year-old suspect was taken to police cells on Thursday night, and was expected to appear before a judge late Friday. Charges had not yet been filed.

"We will be asking that he's not released back into the community," Fincham said.

Possible charges could include assault with a weapon, aggravated assault or even attempted murder, police said.