Toronto, Jun 2 (IANS): As Canadians fear discovery of more graves of indigenous children after the remains of 215 kids were found from the grounds of a former native school, the UN has called for an "exhaustive investigation" into the tragedy.

"Remains should be identified and forensic studies carried out to ensure proper identification of remains. Without this, healing is not possible," the United Nations Human Rights Council told Canada on Wednesday.

The discovery of the remains at the former Indian residential school in Kamloops in British Columbia led to calls on Tuesday for officially designating it as "genocide".

Indian-origin Opposition leader Jagmeet Singh of the New Democratic Party said these schools were started with the aim of a "genocide" of indigenous people.

"These residential schools were not schools; they were institutions designed to eradicate and eliminate Indigenous people. They were institutions that were designed to perpetuate a genocide," he said.

Angry indigenous leaders wanted the Pope to apologise as Catholic missionaries ran these schools with government support.

Canada's first Prime Minister Sir John Macdonald too came under attack as he started these schools in 1883 and ordered Indigenous kids forcibly removed from their "savage" parents and placed in these schools.

Macdonald's statue was removed from the city centre in Charlottetown in Prince Edward Island.

Prime Minister Justin Trudeau, speaking in a House of Commons debate on the tragedy, expressed fears that there could be more unknown graves of indigenous kids at other Indian residential schools.

"We know that the discovery in Kamloops is part of a larger tragedy and that from coast to coast to coast, many children forced into the residential school system disappeared without a trace.

"Today, some of the children who were found in Kamloops - and who have yet to be found in other places across the country - would have been grandparents or great-grandparents. They would have been elders, knowledge keepers and community leaders. They are not. And that is the fault of Canada."

Former Senator Murray Sinclair too feared more unknown graves of indigenous kids who disappeared from the residential schools.

"We know there are lots of sites similar to Kamloops that are going to come to light in the future. We need to begin to prepare ourselves for that," he said.

In all, 139 Indian residential schools ran across Canada where over 150,000 indigenous kids were placed till the last was closed in 1996.