Canadian protesters are now defying a court order as they block a critical route into US

Canadian demonstrators were blocking the busiest international crossing in North America on Saturday in defiance of a court order -- setting up a potential showdown with police over the Covid-19 protests that have snarled supply chains and alarmed political leaders.

On Friday, officials warned that those blocking the Ambassador Bridge between the US and Canada will face severe consequences if they do not clear the critical economic artery that's been shut down for days.

How the Canadian Covid-19 protests could play out

And although the protests have been simmering for more than two weeks, the situation intensified Friday when a judge granted an injunction to the Canadian city of Windsor in Ontario and a manufacturing association to allow police to begin clearing the bridge, which connects the city to Detroit in the US.

Demonstrators could be arrested if they are involved in blocking the bridge, the Windsor Police Service said in a statement. In addition, it warned vehicles may be seized and could be forfeited in the case of a conviction.

The judge gave crowds until 7 p.m. Friday to end the blockade. By midnight, the number of protesters had dwindled, though some remained, according to CNN affiliate WDIV.

Windsor Mayor Drew Dilkens acknowledged the situation could become violent if authorities resort to forcibly removing truckers and protesters, pointing out that conditions could "escalate very, very quickly."

The Premier of Ontario, Doug Ford, also declared a state of emergency on Friday and promised "severe" consequences for those who are taking part in blockades. Fines for non-compliance include a maximum penalty of $100,000 and up to one year in prison.

The Canadian protesters aren't just truckers. Here's who has been showing up and what they want

"So let me be as clear as I can, there will be consequences for these actions, and they will be severe. We've already started by going after the money funding the illegal occupation," Ford said.

Truckers galvanized the demonstrations, which center around disdain for Canada's new rule requiring them to be fully vaccinated when crossing the Canadian-US border or face a two-week quarantine. Their so-called "Freedom Convoy" has since drawn supporters resisting other Covid-19 preventative measures, including mask mandates, lockdowns and restrictions on gatherings.

Canada has one of the highest vaccination rates in the world, with about 4 in every 5 Canadians fully vaccinated, according to data from Johns Hopkins University. And nearly 90% of the country's truckers are fully vaccinated and eligible to cross the border, according to the Canadian government.

Demonstrators, a vocal minority, have used semitrailers and sometimes farm equipment to block key Canadian-US access points at Emerson, Manitoba, and Pembina, North Dakota, as well as at the Coutts access point between Alberta and Montana. And for two weeks, they've blockaded the downtown core of Ottawa, Canada's capital -- including at its main airport -- prompting a judge there to rule they must stop honking.

The Canadian protests, explained

The mayor of Ottawa, Jim Watson, told CNN he expects more demonstrators this weekend.

"It's completely unacceptable," Watson said. "Particularly in the neighborhoods where some of the protesters are going into restaurants and refusing to wear a mask and harassing staff and really being belligerent to the residents of our city."

A protester shouts slogans during a protest by truck drivers over pandemic health rules in Ottawa on February 11.

How Canadian officials are responding to the gridlock

The protesters are demanding that Canadian officials lift the requirement for Covid-19 vaccination for everyone as well as open all businesses including restaurants and gyms. They also want officials to drop capacity limits at large events and eliminate mask mandates -- especially in schools.

But officials have generally stood firm in their appeals to end the blockade, though those calls have fallen on deaf ears.

US business leaders sound the alarm on US-Canada border blockade

Prime Minister Justin Trudeau reiterated that the demonstrations will end.

"If you joined the protests because you're tired of Covid, you now need to understand that you are breaking laws," Trudeau said in a Friday news conference. "You don't want to end up losing your license, end up with a criminal record, which will impact your job, your livelihood."

The Trudeau government said it will send more officers to protests across the country, adding the Royal Canadian Mounted Police, Canada's national police force, continues to show decisive action.

US officials warn similar protests are possible

Small group of Canadian protesters get big support from US conservatives 04:48

Meanwhile, the Canadian protests are igniting concerns among US officials that similar demonstrations may be sparked across the border. Right-wing news media outlets have raised the prospect of like-minded rallies in the US and offered positive coverage of those in Canada.

The protests already are "incredibly damaging" to many across the US Midwest, Michigan Gov. Gretchen Whitmer told CNN on Friday, adding the protests have been "hurting us in Michigan since Day 1."

"We are at an economic crisis because of this illegal blockade," which is becoming a homeland security issue, Whitmer said.

The Department of Homeland Security warned state and local officials in a bulletin that a convoy of truckers protesting Covid-19 vaccine mandates may soon begin in the US and potentially affect the Super Bowl in Southern California.

"The convoy will potentially begin in California as early as mid-February and arrive in Washington, DC, as late as mid-March, potentially impacting the Super Bowl LVI scheduled for 13 February and the State of the Union Address scheduled for 1 March," the bulletin said.

In addition, a group in the US said it is organizing two trucker convoys that will head to the US-Canada border in Buffalo on Saturday and Sunday.

However, the city said Friday the group had not applied for permits to hold events.

"Nor have the organizers contacted our Special Events Office to arrange for the appropriate insurance and public safety planning that is required for all events in the City to ensure the health and safety of residents and visitors," City of Buffalo spokesperson Michael DeGeorge told CNN. "It is always a concern when laws that are designed to keep people and property protected are willfully ignored."