On Thursday, two police buses entered the inner hub of Ottawa after authorities agreed to halt a three-week blockage that caused Prime Minister Justin Trudeau to speak of a “danger to our democracy.”

A CBC reporter shared a video online showing several dozen cops coming off buses a block away from Parliament Hill, where large trucks have been parked since the end of January, some just outside Trudeau’s office.

The apparent reinforcements supplemented an already significant security presence in the center area, which is not normally so publicly policed.

However, there was no immediate sign of a move to clear protesters. Police in Ottawa had on Wednesday handed out flyers warning truck drivers and others paralyzing the downtown core of the city that they should leave or face arrest.

Around 400 vehicles are involved.

“We are going to take back the entirety of the downtown core and every occupied space,” Interim Ottawa Police Chief Steve Bell said in a statement late on Wednesday.

Bad weather could potentially complicate any policing action. A steady rain fell on Ottawa early on Thursday and Environment Canada said this would later turn to snow, with up to 12 inches (30 cm) expected by Friday morning.

Canadian officials have increasingly sharpened their tone, warning of extremist elements present among demonstrators who they say want to overthrow the government.

Trudeau invoked the little-used Emergencies Act on Monday, giving the government a wide range of additional temporary powers. The Royal Canadian Mounted Police have sent in reinforcements and public broadcaster Radio-Canada said the province of Quebec was preparing to provide police.

In a letter on Wednesday to the premiers of the 10 provinces, at least four of whom say there was no need to invoke the act, Trudeau said: “We are seeing activity that is a threat to our democracy and that is undermining the public’s trust in our institutions”.

While the demonstrators initially protested against cross-border COVID-19 vaccine mandates for truckers and pandemic restrictions, they have made clear their opposition to Trudeau and some say they want to kick him out of office.

Tamara Lich, a prominent fundraiser for and organizer of the Ottawa protest, said in a video posted by CTV late on Wednesday: “I’m ready, I’m not afraid, and we’re going hold the line”.

Trudeau is due to address the House of Commons on his decision to invoke the act at 10 am Eastern Time (1500 GMT).