OTTAWA — Thousands of protesters gathered in front of Canada’s Parliament on Saturday in a raucous demonstration, which began as a movement by truckers to challenge a government vaccination mandate but spread to include a wide array of antigovernment grievances.
A loosely organized “Freedom Convoy” of trucks set out last weekend from the western province of British Columbia. The convoy ebbed and flowed in size on the way to Ottawa, the capital, where the police were bracing for what they said would be an unpredictable weekend of protests.
The convoy was organized in response to a regulation, implemented this month, that requires truckers returning from the United States to show proof of vaccination. But it recent days, it has broadened to include Canadians critical of pandemic restrictions in general, and of Prime Minister Justin Trudeau.
Some people, who may not have been involved with the convoy itself, called for an attack on Parliament similar to the Jan. 6, 2021, storming of the U.S. Capitol. Such calls for violence have been denounced by the convoy’s organizers, as well as by many of the protesters on the streets.
Despite fears that the demonstration could turn violent, by Saturday evening the police said there had been no significant incidents.
Private cars and pickup trucks greatly outnumbered the heavy trucks that made up the convoy in its first days. Throughout Saturday, the vehicles clogged the streets in and around Parliament, most of them bearing flags or signs denouncing public health measures related to the pandemic.
Thousands of protesters on foot, many carrying handmade signs on hockey sticks, wandered through the parked vehicles and the slow-moving traffic or gathered on the lawn in front of Parliament. Some of them carried Canadian flags upside down; at least one flag had swastikas drawn on it. The air was filled with diesel fumes and the sound of honking horns.
Few people appeared to be following Ontario’s rules requiring social distancing and masks at crowded, outdoor gatherings.
Watching over it all was a large contingent of police and Parliament security officers. The Ottawa police force was supplemented by officers from towns hundreds of miles away, as well as the Ontario Provincial Police and the Royal Canadian Mounted Police.
The protests were loud and freewheeling but generally peaceful, and poorly organized.
One group affiliated with the convoy intended to try, for a second time, to convince the governor general, Canada’s official (if ceremonial) head of state as Queen Elizabeth’s representative, and the appointed members of the Senate to strike down all pandemic laws and rules imposed by all levels of government — something well beyond their constitutional powers.
Others called for protests outside politicians’ homes. Because the House of Commons is currently not in session — it resumes sitting on Monday — many lawmakers were not in town.
Several Canadian news outlets reported that Mr. Trudeau and his family had been moved out of their official residence by the Royal Canadian Mounted Police as a precaution. The police force declined to comment on the reports, citing security concerns.
Organizers raised about 8 million Canadian dollars, or $6.3 million, on GoFundMe during the convoy’s cross-country trip.
The police towed some vehicles that had been parked on the site of the National War Memorial. Jim Watson, Ottawa’s mayor, said those protesters had disrespected the country’s war dead.
The “Freedom Convoy” was organized by Tamara Lich, secretary of the relatively new Maverick Party, a right-of-center group that was started to promote the separation of Canada’s three western Prairie Provinces from the rest of the country.
While Ms. Lich’s convoy campaign was separate from her work in the Maverick Party, Jay Hill, the party’s interim leader, said the convoy had tapped into what he believed to be widespread sentiment in Canada against pandemic restrictions.
“This thing has really taken on a life of its own,” said Mr. Hill, a former Conservative member of Parliament from Alberta. “The vast majority of the people that have either come on board to participate in the truck convoy or those donating to support it financially have just reached a point of frustration and exasperation with these lockdowns and continuation of restrictions that they want someone to speak up and say ‘enough’ to the federal government.”
But opinion polls have consistently shown strong support in Canada for public health measures to limit the spread of the coronavirus, which have mostly been imposed by provincial governments, many of them led by Conservatives. More than 77 percent of Canadians are fully vaccinated.
Several people in the crowd on Saturday said they believed vaccines were potentially harmful and ineffective, despite overwhelming scientific evidence to the contrary.
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Mr. Trudeau has called the protesters a “small fringe minority.” He has repeatedly said that 90 percent of Canada’s truckers are vaccinated, an assessment shared by the Canadian Trucking Alliance, a trade group that opposes the protest.
On Saturday, that group issued a statement indicating that the protesters did not represent the views of most truckers.
“We ask the Canadian public to be aware that many of the people you see and hear in media reports do not have a connection to the trucking industry,” it said.
Vaccination mandates for ship crews, railways and airline workers have been in effect since Oct. 30. On Jan. 15, they were extended to truck drivers returning from the United States. The requirement does not apply to the vast majority of the country’s more than 300,000 truckers who drive domestic routes.
The protesters, and several Conservative members of Parliament, have blamed the new mandate for shortages of goods.
“You probably noticed some empty shelves at your grocery store,” Erin O’Toole, the leader of the Conservative Party, said in an online video posted on Thursday. “That’s because Justin Trudeau put in a place a mandate that all truckers entering this country, either Canadian or American, have to be fully vaccinated.”
But David Soberman, a professor who studies logistics at the Rotman School of Management at the University of Toronto, said that empty shelves in Canadian shops were mostly linked to other factors, like a global shortage of shipping containers, disruptions in the production of some products and a lack of employees to replenish shelves because of Covid infections.
“There’s definitely amplification and fear-mongering going on by the people who are not happy about this rule,” he said. “But I don’t really think it is actually having a major impact on supermarkets in Canada.”
Mr. Trudeau has made it clear that the protest will not lead his government to reverse the vaccine mandate. In any case, doing so would have no practical effect: The United States made vaccines mandatory for Canadian truckers crossing its border as of Jan. 22.
Omar Alghabra, the transport minister, told the Canadian Broadcasting Corporation on Friday that there had been no meaningful decline in cross-border truck traffic since either country’s vaccine mandate was put in place.
The protesters’ next steps were unclear. As the sun set on a bitterly cold day, the crowd had noticeably thinned. Some of those who remained, still a significant number, vowed to stay until the cross-border vaccine mandate was removed.
“At some point, the organizers — if we can call them that — have to say, ‘All right, it’s time to move on and allow the people of Ottawa to get back to some sense of normalcy,’” Mr. Watson, the mayor, told CityNews Ottawa, a broadcaster.
