OTTAWA: The progress Canada has made against COVID-19 is being threatened by the spread of more contagious and dangerous virus variants, Prime Minister Justin Trudeau said on Tuesday in notably downbeat remarks.

"The situation we're facing with COVID-19 remains extremely serious ... this is not the place anyone wanted to be," Trudeau said, citing a rapid rise in the number of cases and an increasingly strained healthcare system.

Ontario, the most populous of the 10 provinces, reported a single-day high of new COVID-19 cases on Sunday and has closed schools to in-person learning.

Frustration about shutdowns is rising across the country and rioters in Montreal smashed windows in the downtown area over the weekend.

Canada is due to import enough doses to ensure every person can receive at least one shot by the end of June, but the pace of vaccinations is dragging in the race to get people inoculated as the concerning variants increase spread of the coronavirus.

"Right now, more contagious and dangerous variants are spreading and threatening the progress we've made," Trudeau told a briefing.

Chief public health officer Theresa Tam said new cases had risen by 33pc over the last week.

The number of daily cases is now over 8,100, about the same as during the peak of the second wave earlier this year.