More than 750 unmarked graves have been found near a former Catholic boarding school for indigenous children in western Canada, a tribal leader said on Thursday.
It was the second such shock discovery in less than a month.
The find again cast a spotlight on a dark chapter in Canada's history, and revived calls for the Pope and the Church to apologise for the abuse and violence suffered at the schools, where pupils were forcibly assimilated into the dominant culture.
"As of yesterday, we have hit 751 unmarked graves" at the site of the former Marieval boarding school in Saskatchewan province, Cowessess First Nation Chief Cadmus Delorme said.
"This is not a mass grave site. These are unmarked graves."
Mr Delorme said each grave would be assessed in the coming weeks to determine the final number of victims whose remains are at the site.
He said the graves may at one time have been marked, but "Catholic Church representatives removed these headstones".
Mr Delorme said doing so was a crime in Canada and they were treating the site "as a crime scene".
Last month the remains of 215 children, some as young as 3 years old, were found buried on the site of what was once Canada's largest Indigenous residential school near Kamloops, British Columbia.
From the 19th century until the 1970s, more than 150,000 First Nations children were required to attend state-funded Christian schools as part of a programme to assimilate them into Canadian society.
They were forced to convert to Christianity and not allowed to speak their native languages.
Many were beaten and verbally abused and up to 6,000 are said to have died.
Canadian Prime Minister Justin Trudeau said he was "terribly saddened" by the new discovery at Marieval Indian Residential School, about 140 kilometres from the provincial capital Regina.
Mr Trudeau told indigenous people that "the hurt and the trauma that you feel is Canada’s responsibility to bear".
"Together, we must acknowledge this truth, learn from our past and walk the shared path of reconciliation, so we can build a better future," he said.
The Canadian government apologised in Parliament in 2008 and admitted that physical and sexual abuse in the schools was rampant.
Many pupils recall being beaten for speaking their native languages. They also lost touch with their parents and customs.
Indigenous leaders say the legacy of abuse and isolation was the root cause of epidemic rates of alcoholism and drug addiction on reservations.