As truck blockades in Canada spread to include three Canada-US border crossings, the White House said Wednesday the protests threaten the auto industry supply chain. 

"We are watching this very carefully," White House spokeswoman Jen Psaki said at a news briefing. "The blockade poses a risk to supply chains, for the auto industry."

Meanwhile, a nearly two-week truck blockade continues to paralyze the capital, Ottawa, which declared a state of emergency earlier this week.

Prime Minister Justin Trudeau said during an emergency debate of the House of Commons this week that the Ottawa protesters are "trying to blockade our economy, our democracy and our daily lives. It has to stop.”

"The people of Ottawa don't deserve to be harassed in their own neighborhoods."

Protesters are demanding that all mandated coronavirus vaccine measures be ended by the government.

In Toronto, Canada's largest city, with a population of about 2.8 million, police took action Wednesday to secure road entry points to Queen's Park, the provincial government headquarters in the downtown.

The Ambassador Bridge spans the Detroit River, linking Windsor, Ontario to Detroit and about CAN$400 million (US$316 million) in trade between the two countries passes daily. It is the main crossing for auto parts and agricultural products.

The blockade entered its third day Wednesday.

Windsor Mayor Drew Dilkens said Wednesday that the police are not removing the 50-75 vehicles at the crossing because violence could break out.

“You have a number of people who are…part of the protest group who have openly stated…they feel such a passion for this particular cause that they are willing to die for it,” Dilkens said.

At Coutts, Alberta, protests in support of the Ottawa blockade began Jan. 30 and grew to strand cross-border truckers. Millions of dollars in trade is routed through the Coutts crossing. Police said Wednesday they are prepared to act but preferred that the demonstrators moved on their own.

Yet another blockade was created at Sarnia, near Windsor, where transport trucks were backed up while trying to cross into the US by the Blue Water Bridge.

Meanwhile in Ottawa, about 500 trucks continued to shut down the city and the protesters remain "volatile," said Ottawa Police Deputy Chief Steve Bell.

Police there had made 22 arrests and issued more than 1,300 tickets for idling, noise and open-fire violations./aa