Canada's early COVID-19 cases came from the United States and not China, The National Post reported Thursday.

Although the coronavirus pandemic was first reported in Wuhan, China, the data from Canada's largest four provinces show it was American travelers, not Chinese, who brought the COVID-19 to Canada, according to the newspaper.

However, the Canadian government placed travel restrictions on China first and American border restrictions later in its public safety measures.

Canada issued an official travel advisory for parts of China in late January, when the federal government implemented "heavy travel restrictions" affecting many cities throughout the Chinese provinces.

International visitors were barred from entering Canada, and only Canadian citizens and permanent residents were allowed to return.

It wasn't until mid-March that the US and Canadian governments decided to restrict tourists and visitors from crossing the border on both sides.

The National Post asked for data on the origins of travel-related cases in Ontario, Quebec, British Columbia and Alberta, the four provinces that have seen the majority of Canada's COVID-19 cases.

According to the data, as of April 17, Ontario had identified 1,201 cases of COVID-19 in people who had recently returned from international travel. Among those cases, "just five related to travel from China. By contrast, 404 were from people traveling from the United States".

The other top five destinations for Canadians were the UK, Mexico, Spain, Iran and Italy, and they "are also more heavily represented than China", according to the National Post.

The data also show that most of the cases in Quebec came from the US and "the province reports zero cases connected to travel from China", the Post said.

Alberta had "only a single case connected to China, while 36 percent of its travel-related cases are from the United States". British Columbia's data show that while its first cases were travel related, most came from community spread.

As of 6:30 pm EDT Thursday, Canada had more than 53,000 coronavirus cases and nearly 3,200 COVID-19 deaths. Deaths in nursing homes and long-term care facilities make up 79 percent of COVID-19 fatalities, according to Canadian government data.

Total cases of COVID-19 across Canada could reach 66,835 by May 5, according to the worst-case projections, according to government data.

Canada's coronavirus curve is flat, but some worrying trends are emerging, particularly outbreaks in vulnerable indigenous communities, the country's top medical officer said on Thursday.

"This week things have been a little flat — the COVID-19 curve is flat, that is ... we have to be very cautious going down the other side of the epidemic curve," Chief Public Health Officer Theresa Tam told a briefing.

"Already on this path we have seen some worrisome transmission events emerging," she said, citing increasing numbers of cases in remote aboriginal communities in several of Canada's 10 provinces.

Health officials say the virus spreads quickly in environments often where vulnerable people are gathered, such as seniors' residences, prisons and far-flung parts of the country where healthcare availability is already uneven.

Reuters contributed to this story.