Tensions are rising at one of the US-Canada border's busiest ports of entry over a vehicle blockade that has halted traffic and disrupted services.
The demonstration is tied to the ongoing nationwide "Freedom Convoy" protests over Canada's new restrictions on unvaccinated cross-border truckers.
Some motorists and local residents have reportedly been stuck in standstill since the protest began on Saturday.
The Royal Canadian Mounted Police in Alberta said the event was "unlawful".
They said "extensive efforts" to negotiate with protest organisers had failed and the force has tapped "additional resources" to make arrests or tow trucks if needed.
"While we thought we had a path to resolve this, the protesters chose not to comply," a statement said.
The Freedom Convoy began as a call to end a federal vaccine mandate that would require unvaccinated Canadian truckers returning from across the US border to quarantine and get tested once they are home.
It has since grown into a push to end all vaccine mandates nationwide and what supporters see as government overreach on Covid-19 restrictions.