A crucial trade route between Canada and the US has been reopened following a weeklong-protest by lorry drivers and anti-lockdown demonstrators as police moved to clear the disruption.

The Ambassador Bridge, the busiest border crossing in North America that connects Windsor, Ontario and Detroit, Michigan, had been closed by a group of anti-vaccine mandate protesters. Detroit International Bridge Co, the bridge’s owner, said on Sunday it was “fully” open allowing the free flow of commerce”, according to the Associated Press.

The protesters are part of the self-styled “Freedom Convoy” that has occupied Ottawa, Canada’s capital, for two weeks. What began as a narrow demonstration against a requirement that truck drivers crossing the Canada-US border be vaccinated against Covid-19 has swelled into a vast, foreign-funded anti-government protest.

Drew Dilkens, the mayor of Windsor, said: “This is no longer just about vaccine mandates and mask mandates, this is more to do with an anti-government protest and it is leaderless.”

Justin Trudeau, Canada’s centre-left prime minister, has become the main target of the protesters’ anger. His office said on Sunday that the Royal Canadian Mounted Police had established a co-ordinated command centre with provincial and municipal law enforcement to deal with the demonstrations, and warned that “consequences for breaking the law will be increasingly severe”.

As well as blocking Ambassador Bridge, the protesters have laid siege to Ottawa and clogged traffic at another border crossing in Coutts, Alberta. The Freedom Convoy does not have the support of trade unions representing truckers.

On Friday, a judge ordered an end to the blockade, while Doug Ford, premier of Ontario, declared a state of emergency, threatening those that blocked roads and bridges with C$100,000 (US$79,000) fines and a year in jail. Police intervened on Saturday morning after the court-mandated deadline of 7pm on Friday had passed.

Yet police said 4,000 demonstrators had massed in Ottawa on Saturday, many dressed in camouflage, and marched through residential neighbourhoods waving flags and chanting “Freedom”.

Police stood by as protesters removed barricades at Ottawa’s National War Memorial, which had been installed after people urinated on it and danced on the Tomb of the Unknown Soldier during the protest’s first weekend.

“This isn’t just Ottawa, it’s the nation’s capital. But no one — not the city, the province, or the federal government — can seem to get their act together to end this illegal occupation,” Catherine McKenna, a former cabinet minister in Trudeau’s government, wrote in a social media post.

Ambassador Bridge supports more than a quarter of trade between Canada and the US, accounting C$400mn (US$314mn) of daily trade, according to Dilkens.

The blockade has prompted concern from the White House about supply chain disruptions. Last week, US president Joe Biden asked Canada to use federal powers to end the blockade, but Trudeau said he was not considering deploying the army.

Manufacturers have already suffered supply chain interruptions. Ford, the second-largest US carmaker, said on Friday that it had stopped work at its Ohio assembly plant, while Toyota and General Motors announced production cuts.

The White House said on Sunday it was working closely with the Canadian government to help clear blockades on crossings between the countries and expected the Ambassador Bridge to reopen later in the day.

Thousands of anti-vaccine mandate protesters descended on Ottawa at the end of January, when about 400 trucks blocked streets in front of parliament for a fortnight. The protesters erected a stage, a screen, a bar tent, kitchens, bouncy castles and a hot tub. The hooting of vehicle horns has continued despite an injunction issued by a judge last week.

The protests have won the backing of high-profile figures on the US right wing, including former president Donald Trump, and inspired similar actions in France, New Zealand, the US and Australia.

Additional reporting by Kiran Stacey in Washington