Hundreds of unmarked graves found for second time at former school for Indigenous children in Canada

Credit: AP

At least 600 unmarked graves have been discovered at the side of a former residential school for Indigenous children in Canada.

It is the second time graves have been found in Saskatchewan as the country has been met with grief and outrage over one of the darkest chapters of its history.

Investigators discovered the graves at the Marieval Indian Residential School, which operated from 1899 to 1997, Chief Cadmus Delorme of the Cowessess First Nation, said on Thursday.

Mr Delmore said the graves were marked at one time, but the Roman Catholic Church that operated the school had removed the markers.

"The Pope needs to apologise for what happened," he said, before adding: "An apology is one stage in the way of a healing journey."

A memorial is seen outside the Residential School in Kamloops, British Columbia. Credit: AP

The Cowessess First Nation began a ground-penetrating radar search on June 2 - after the discovery of 215 unmarked graves at the Kamloops Residential School in British Columbia outraged the country. 

Mr Delorme said the radar resulted in 751 "hits" which indicates at least 600 bodies were buried in the area.

"We want to make sure when we tell our story that we’re not trying to make numbers sound bigger than they are... I like to say over 600, just to be assured," Mr Delorme said.

He said the search continues and the radar hits will be assessed by a technical team and the numbers will be verified in coming weeks.

A memorial is seen outside the Residential School in Kamloops, British Columbia. Credit: AP

"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.

He said he expects more graves will be found on residential school grounds across Canada.

"We will not stop until we find all the bodies," he added.

Last month, the remains of 215 children, some as young as three years old, were found buried on the site of what was once Canada’s largest Indigenous residential school near Kamloops, British Columbia.

A vigil for the 215 children whose remains were found buried at the former Kamloops Indian Residential School Credit: Darryl Dyck/The Canadian Press via AP

Following that discovery, Pope Francis expressed his pain over the discovery and pressed religious and political authorities to shed light on "this sad affair".

But he did not offer the apology sought by First Nations and by the Canadian government.

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, in a campaign to assimilate them into Canadian society.

The Canadian government has admitted that physical and sexual abuse was rampant in the schools, with students beaten for speaking their native languages.