751 unmarked graves at former Residential School in Saskatchewan

Warning: this story contains details that are disturbing.

Cowessess First Nation says it has found an estimated 751 unmarked graves at the site of a former Residential School in Saskatchewan.

Marieval Indian Residential School was operational from 1899 to 1997.

The school was first run by four sisters of the Congregation of Our Lady of the Missions and subsequently by the Sisters of Saint Joseph of Saint-Hyacinthe from 1901 to 1979. The running of the school was transferred from the Roman Catholic Church to the government of Canada in 1969.

Last month 215 bodies were discovered at a former Residential School in Kamloops British Columbia.

Prime Minister Justin Trudeau said in a statement, "My heart breaks for the Cowessess First Nation, and for all Indigenous communities across Canada."

A National Indian Residential School Crisis Line has been set up and will be operational 24 hours a day at 1-866-925-4419.

Earlier story: Hundreds of unmarked graves found at former Saskatchewan residential school