Investigators in Canada have reportedly found 751 unmarked graves at the site of a former school for Indigenous children.
The bodies were discovered at the Marieval Indian Residential School about east of Regina, the capital of Saskatchewan.
The find comes just weeks after 215 graves of children were found at another school in British Columbia.
The number of graves found is reported to be "most significantly substantial to date in Canada".
"This was a crime against humanity, an assault on First Nations," said Chief Bobby Cameron of the Federation of Sovereign Indigenous First Nations in Saskatchewan.
"We will not stop until we find all the bodies," he stated, adding that he expects more graves will be found on residential school grounds across Canada.
From the 19th century until the 1970s, more than 150,000 Indigenous children were forced to attend state-funded Christian schools, the majority of them run by Roman Catholic missionary congregations.
The move was aimed to assimilate the children into Canadian society, but Canada's government has admitted that physical and sexual abuse was rampant in the schools, with students beaten for speaking their native languages.
The Marieval Indian Residential School operated from 1899 to 1997 where the Cowessess First Nation is now located.
Chief Cadmus Delmore of the Cowessess said that the graves were marked at one time, but that the Roman Catholic Church that operated the school had removed the markers.
"The Pope needs to apologise for what happened,'' he said, "an apology is one stage in the way of a healing journey."
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.
Following that discovery, Pope Francis expressed his pain and pressed religious and political authorities to shed light on the "sad affair".
The Pope did not however offer an apology, as requested by First Nations and Canadian Prime Minister Justin Trudeau.