Three people were charged in relation to the protest ,while 25 investigations are ongoing. (File)
Most protesters who recently packed the streets of Canada's capital and jarred locals with loud honking trucks have left, but the stragglers are "determined" and "volatile," police warned Wednesday.
Their numbers are expected to surge again, possibly into the thousands this weekend, as well as spread to other parts of the nation.
"Most demonstrators have left. What remains is a highly determined and highly volatile group of unlawful individuals," Ottawa Deputy Police Chief Trish Ferguson told a briefing.
Police estimate 15,000 rowdy protesters opposed to Canada's COVID-19 vaccine mandate and other public health measures converged on Ottawa's downtown over the weekend, bringing the city to a virtual standstill.
Three people were charged in relation to the protest ,while 25 investigations are ongoing.
By Wednesday, after having forced most downtown businesses -- including a major mall, schools and Covid vaccine clinics -- to shutter, the protesters' numbers had dwindled to a few hundred, and they were mostly contained to the parliamentary precinct.
But a solidarity blockade in western Alberta province of Highway 4 along the US border was flaring up. The road is a major artery for commercial goods between the nations.
Police moved in Tuesday evening to try to dislodge the 100 or so truckers on the Alberta-Montana border, but as a few left, more arrived.
"We had three or four vehicles voluntarily just say, 'Yeah, okay, I've had enough and I'm out of here,' and they began to leave. Then several vehicles... broke through a checkpoint that we had set up," RCMP Corporal Curtis Peters told AFP.
Some of them, he said, drove tractors and other farm vehicles through fields to get around the police checkpoint.
Meanwhile, another protest is reportedly planned for Quebec City in the coming days.
Ottawa police Chief Peter Sloly said authorities "are now aware of a significant element from the United States that have been involved in the funding, the organizing and the demonstrating."
"They have converged in our city, and there are plans for more to come," he said, without providing details.
An online GoFundMe campaign has raised more than Can$10 million (US$8 million) in support of the so-called "Freedom Convoy" protests.
Several US figures, including Donald Trump Jr and Elon Musk, have also tweeted their support for the protesters.