OTTAWA (Reuters) — Canada’s capital city of Ottawa is set on Saturday for a “massive” protest against Prime Minister Justin Trudeau’s COVID-19 vaccine mandates with the arrival of convoys of hundreds of vehicles from across the country.

The so-called “Freedom Convoy” — coming from east and west — started out as a protest against a vaccine requirement for cross-border truckers but has turned into a demonstration against government overreach during the pandemic with a strong anti-vax streak.

The convoys are scheduled to get in around noon, but already on Friday dozens of vehicles blocked the roads in front of Parliament. A total of some 2,700 trucks are expected, a federal government source said.

“These demonstrations are national in scope, they’re massive in scale,” Ottawa Police Chief Peter Sloly said on Friday. “We do not know all of the parallel demonstrations that may occur and where the lone wolf individuals may insert themselves into the mix for various reasons.”

Sloly added that teams will be videotaping “all aspects of the demonstration” and warned that anyone breaking the law will be arrested.

Trudeau on Friday said he was concerned about the protest turning violent in an interview with the Canadian Press, and said this week the convoy represented a “small fringe minority” who “do not represent the views of Canadians.”

Trudeau announced a vaccine mandate for federal workers in October on the eve of the election, and then last month both Canada and the United States imposed one for cross-border truckers.

Conservative leader Erin O’Toole opposes vaccine mandates and has expressed support for the protest, pledging to meet some truckers and posting a video on social media blaming Trudeau for potential supply chain problems the trucker mandate may cause.

The Canadian Trucking Alliance, which represents some 4,500 carriers, opposes the protest, saying this is “not how disagreement with government policies should be expressed.”

About 90% of Canada’s cross-border truckers and 77% of the population has had two shots.

(Reporting by Steve Scherer, additional reporting by David Ljunggren, editing by Alistair Bell.)