Canadian police on Saturday worked to restore normality to the capital after trucks and demonstrators occupied the downtown core of Ottawa for more than three weeks to protest against pandemic restrictions.

The push to clear the city began on Friday and continued into the night.

Four of the main organizers have already been taken into custody and more than 100 protesters have been arrested as hundreds of officers, including some on horseback, formed lines and slowly pushed them away from their vehicles.

There were many tense moments on Friday. Some protesters were dragged from their vehicles, and others who resisted the police advance were thrown to the ground and had their hands zip-tied behind their backs.

Police said protesters had showed "assaultive behavior", and once police on horseback were brought in to "create space," according to a statement.

The protesters initially wanted an end to cross-border Covid-19 vaccine mandates for truck drivers, but the blockade has gradually turned into an anti-government and anti-Prime Minister Justin Trudeau demonstration.

"Our demands aren't ridiculous. We want mandates and lockdowns dropped," said Gord from Manitoba, a truck driver who said he cannot work anymore because of cross-border vaccine mandates. On Friday, he vowed to stay parked in front of parliament and said he was waiting to be arrested.

Trudeau on Monday invoked emergency powers to give his government wider authority to stop the protests. Legislators had been due to debate those temporary powers on Friday but the House of Commons suspended its session, citing police activity.

After the protest crowds swelled on the three previous weekend, police set up 100 road blocks around the downtown core on Friday to deny people access and prevent food and fuel from getting in. Police said they had towed 21 vehicles on Friday.

As police cleared protesters from the streets, at least a dozen tow trucks came in to remove trucks and other protest vehicles still parked downtown.