At first, no one found it suspicious that the black Audi SUV had gone around a portable barrier into a street packed with festivalgoers lining up at food trucks and checking out artisans’ wares.

It was about 8 p.m. Saturday, and Apl.de.ap, a Filipino American rapper and a founding member of the Black Eyed Peas, had finished a concert that was the signature event of the Lapu Lapu Festival organized by the Filipino community in Vancouver, British Columbia.

At first the large SUV crawled through the crowd, and Kris Pangilinan, who was selling clothing at a booth, assumed that it had been let in to help another merchant load up his wares and close shop.

Then, it started to speed up.

“He sideswiped someone where the vendors are,” Mr. Pangilinan said on Sunday after a largely sleepless night. “All of a sudden I hear this exhaust and the sound of the acceleration of the vehicle. Then, boom: He hits dozens of people.”

Shortly afterward, police officers were commandeering the tables in Mr. Pangilinan’s tent to use as makeshift stretchers.

At least 11 people, ranging in age from 5 to 65, were killed in the episode, which Prime Minister Mark Carney described as a “car-ramming attack.” Dozens more were injured, the interim chief of the Vancouver Police Department, Steve Rai. said Sunday, warning that it was likely that some of them may die.

Several witnesses said the driver of the SUV tried to run away after the attack but was restrained by people in the crowd. A 30-year-old man was in custody on Sunday, although no charges have been brought yet, Mr. Rai said.

He declined to discuss the suspect’s motive, but said that the police previously had “substantive contact with him over mental health issues.” David Eby, the premier of British Columbia, said that the driver had acted “intentionally.”

The police have ruled out terrorism as a motive, an assessment that was shared by national security officials, according to Mr. Carney. “We do not believe there is any active threat to Canadians,” he said.

Throughout Saturday night and into Sunday, members of Vancouver’s large Filipino community were frantically exchanging messages to determine whom they had lost, who was injured and who had escaped the carnage.

“I don’t think my phone buzzed that much my entire life,” said R.J. Aquino, the chairman of the Filipino Canadian Community and Cultural Society of B.C. “There was a lot of panic, and relief when somebody answers.”

Mable Elmore, a provincial lawmaker and festival organizer who turned her office into a refuge for people fleeing the killing, struggled, and sometimes failed, to maintain her composure at a news conference.

“It was a beautiful day for a celebration,” she said, recalling the ideal weather the festival had been graced with.

Lapu Lapu Day, an annual celebration in the Philippines, commemorates Datu Lapu Lapu, an Indigenous leader who stood up against Spanish colonization. In Vancouver, the festival became an annual event in 2023.

“We are in incredible pain,” Ms. Elmore said. “The Filipino community will show true resilience, and we will come together out of this catastrophe with the support and the love from the broad community.”

The attack upended the final day of campaigning in a Canadian election that has been dominated by President Trump’s tariffs and his vow to annex Canada as the 51st state. Mr. Carney and Jagmeet Singh, the leader of the third-place New Democratic Party, both largely abandoned their schedules for Sunday. Mr. Carney still planned to go to Vancouver, but to meet with mourners rather than rally his supporters.

“Last night, families lost a sister, a brother, a mother, a father, a son or a daughter,” Mr. Carney told reporters in Hamilton, Ontario. “Those families are living every family’s nightmare.”

Addressing Filipino Canadians, he said: “I join all Canadians in mourning with you. I know Canadians are united with you.”

Pierre Poilivere, Mr. Carney’s Conservative rival, continued to campaign but made an appearance at a Filipino church in suburban Toronto.

President Ferdinand R. Marcos Jr. of the Philippines said in a statement on Sunday that he was “completely shattered to hear about the terrible incident” in Vancouver, and he expressed his “deepest sympathies” to the families of the victims.

Vancouver prides itself on being a diverse, multicultural city, with more than half of its residents identifying themselves as a “visible minority,” according to 2021 census.

Mr. Eby, the province’s premier, noted on Sunday that Filipinos are prominent in health and child care as well as in the workforces of long-term care homes.

“We’re going to stand with them and support them just like they support us,” Mr. Eby said. “It’s their turn to get care from us.” ”

A hip-hop artist who performed at the festival, Jacob Bureros, said he was signing autographs, posing for photos and “feeling on top of the world” when he heard the SUV tear through the crowd and then saw the driver try to escape.

“He gets out of the car, takes off, and I start running to the left,” Mr. Bureros said. “Three of us surrounded the guy, screaming at him.” He said a security guard and event organizer stepped in to protect the suspect from retaliation.

This was the first mass killing involving a vehicle in Canada since 2021, when a far-right extremist drove a pickup truck into five members of a Muslim family in London, Ontario, killing four of them. A judge determined that the man was motivated by white supremacist ideology and deemed the killings to be an act of terrorism.

In 2018, a man in Toronto used a rented van to run down and kill 11 pedestrians, injuring another 15. Most of the victims were women.

In recent years, police forces in Canada have regularly blocked roads leading to venues hosting large crowds with snowplows or gravel-filled dump trucks.

That step was not taken around the scene of the Vancouver attack.

Underscoring the authorities’ initial assessment that the attack was an isolated event, the police allowed a 10-kilometer run that drew more than 45,000 entrants last year to go ahead on Sunday.

The one-off nature, however, did little to console many in the Filipino community.

“Why us — why they would harm such a beautiful community?” Mr. Pangilinan, the merchant, asked. “It’s definitely something that I’m going to have to live with for the rest of my life. And we will just pay tribute to those affected and those who died.”

Sarah Berman contributed reporting from Vancouver.