An Indigenous nation in Canada said it has found the remains of 182 people near the grounds of a former residential school in British Columbia.

The Lower Kootenay Band said it is too early to say if the remains belonged to former students of the school.

But the discovery adds to a rising tally of such unmarked grave sites across the country.

The grim finds have prompted national outrage and fuelled calls by some to cancel the 1 July Canada Day holiday.

Indigenous leaders have said they expect more graves will be found as investigations continue.

"You can never fully prepare for something like this," said Chief Jason Louie of the Lower Kootenay Band, which is a member of the Ktunaxa Nation.

The community of ʔaq'am, one of four bands in the Ktunaxa Nation, used ground-penetrating technology to uncover the gravesites close to the former St Eugene's Mission School near Cranbrook, British Columbia.

Some remains were found in shallow graves, only 3-4ft deep, the Lower Kootenay Band said in a statement.

St Eugene's was operated by the Catholic Church from 1912 until the early 1970s. It was one of more than 130 compulsory boarding schools funded by the Canadian government and run by religious authorities during the 19th and 20th Centuries with the aim of forcibly assimilating indigenous youth.

Up to 100 of the Lower Kootenay Band were forced to attend, the group said.

But the remains were found on the grounds of the ʔaq̓am cemetery, which dates back to 1865. Burial plots used to be marked with wooden crosses that crumbled over the years.

"These factors, among others, make it extremely difficult to establish whether or not these unmarked graves contain the remains of children who attended the St Eugene Residential School," the community's statement said.

The news comes amid a national soul-searching over Canada's legacy of residential schools.

In May, the remains of 215 Indigenous children were found in unmarked graves in Kamloops, British Columbia. Then last week, leaders for the Cowessess First Nation said the remains of 751 bodies, most of them children, were discovered at the former site of another school in Saskatchewan.

And this most recent discovery comes on the eve of Canada Day, 1 July, meant to mark the same date in 1867 when three British colonies were joined to create the Dominion of Canada.

Many Indigenous people in Canada have never recognised Canada Day, a sentiment that has grown in recent weeks. Municipalities across Canada have cancelled upcoming celebrations and statues of figures involved with residential schools have been vandalised or removed throughout the country.

Speaking on Wednesday, Prime Minister Justin Trudeau said the discoveries "have forced us to reflect on the historic and ongoing injustices that Indigenous peoples face".

Canada Day is "going to be a day where we celebrate", said Mr Trudeau. "But we will mostly reflect on the work that we all have to do."