The remains of 215 children, some as young as three years old, were found at the Kamloops Indian Residential School in British Columbia that closed in 1978, the Tk’emlúps te Secwépemc Nation said on May 28.

“We call for a thorough and impartial investigation into all cases where crimes were committed against the indigenous people, especially children, so as to bring those responsible to justice, and offer full remedy to victims,” Jiang Duan, a senior official at China’s mission to the United Nations in Geneva, told the Human Rights Council.

Canada, locked in a trade and diplomatic dispute with Beijing, later delivered a joint statement on behalf of more than 40 countries calling for access to China’s Xinjiang region to look into allegations of the government’s mass detention of Uyghur Muslims.

Trudeau, condemning what he called “the systemic abuse and human rights violations” in Xinjiang, said a Canadian truth and reconciliation commission had worked from 2008 to 2015 to address the mistreatment of the indigenous population.

Where is China’s truth and reconciliation commission? Where is their truth? Where is the openness that Canada has always shown and the responsibility that Canada has taken for the terrible mistakes of the past?” Trudeau asked.

“China is not recognising even that there is a problem … that is why Canadians and people from around the world are speaking up for people like the Uyghurs,” Trudeau told reporters in Ottawa.

Jiang read the statement out on behalf of countries such as Russia, Belarus, Iran, North Korea, Syria and Venezuela, all of which have been criticised by Western nations for human rights violations.

Canada’s residential school system, which forcibly separated indigenous children from their families, constituted “cultural genocide,” the truth and reconciliation commission said in 2015.