It has been termed as "the most significantly substantial to date in Canada" by the Cowessess First Nation on Wednesday.

However, they did not specify the exact number of graves found.

The discovery comes weeks after remains of 215 children were found at a British Columbia residential school.

"Such compulsory boarding schools were run by the Canadian government and religious authorities during the 19th and 20th Centuries with the aim of assimilating indigenous youth," a BBC report said.

The indeginous group began to use ground-penetrating radar to locate unmarked graves at the cemetery of the Marieval Indian Residential School in Saskatchewan in May, according to reports.

Further details pertaining to the recent discovery will be revealed during a news conference on Thursday.

Perry Bellegarde, national chief of the Assembly of First Nations, stated the finding as "tragic but not surprising".

"I urge all Canadians to stand with First Nations in this extremely difficult and emotional time," he wrote on Twitter.

In a period spanning a little over 130 years, between 1863 and 1998, more than 150,000 indigenous children were placed in these schools, after being taken from their families. What would follow them were abuse and mistreatment. The children were barred from speaking their language or practicing their culture.

In 2008, the Canadian government formally apologised to the indigenous community after a commission, launched in 2008 to document the impacts of this system, reported that large numbers of indigenous children never returned to their home communities, reports said.