The remains of 215 children have been found buried on the site of a former residential school in Kamloops, B.C.

Chief Rosanne Casimir of the Tk'emlups te Secwepemc First Nation says in a news release that the remains were confirmed last weekend with the help of a ground-penetrating radar specialist.

Casimir calls the discovery an ``unthinkable loss that was spoken about but never documented at the Kamloops Indian Residential School.''

She says it's believed the deaths are undocumented, although a local museum archivist is working with the Royal British Columbia Museum to see if any records of the deaths can be found.

She says the children, some as young as three and were students at the school, once the largest in Canada's residential school system.

The chief says work to identify the site was led by the First Nation's language and cultural department alongside ceremonial knowledge keepers, who made sure the work was done was in line with cultural protocols.

Federal Minister of Crown-Indigenous Relations, Carolyn Bennett, says in a social media message that a crisis line is available for anyone needing support and the federal government is ready to support healing and honour the loved ones lost.