Police said they were investigating a mass casualty incident and had arrested a 30-year-old Vancouver man at the scene, but did not immediately give the number of fatalities or injured, saying they would have more information in the morning.

"At this time, we are confident that this incident was not an act of terrorism," Vancouver police said in an X post.

At a midnight press conference, police said that the suspect was "known" to them but did not elaborate. The man was initially taken into custody by people at the scene.

The incident happened shortly after 8 p.m. (0300 GMT) near East 41st Avenue and Fraser Street, where the Lapu Lapu Day Block Party, celebrating a Philippine national hero, was taking place.

Canadian Prime Minister Mark Carney said on X: "I am devastated to hear about the horrific events at the Lapu Lapu festival in Vancouver earlier this evening."

Vancouver's Mayor Ken Sim and British Columbia Premier David Eby posted similar comments on X.

One witness told CTV News he saw a black vehicle driving erratically in the area of the festival just before the crowd was struck.

Jagmeet Singh, leader of Canada's New Democratic Party, was among the attendees at the event, but left minutes before the vehicle arrived, CTV News said.

"This is so horrific, I don't even know what to say," CTV quoted Singh as saying. "I was just there, and I just imagine the faces of the kids that I saw smiling and dancing."

Canada's federal election takes place on Monday.

The Vancouver Sun said thousands of people had been in the area.

"I didn’t get to see the driver, all I heard was an engine rev," Yoseb Vardeh, co-owner of food truck Bao Buns, said in an interview with Postmedia.

"I got outside my food truck, I looked down the road and there’s just bodies everywhere,” said Vardeh, as his voice broke. "He went through the whole block, he went straight down the middle."