A long-awaited report into Canada's decades-long government policy requiring Canadian Indians to attend state-funded church schools called it "nothing less than cultural genocide."

Truth and Reconciliation Commission chair Justice Murray Sinclair said Tuesday that residential schools are one of the "darkest and most troubling chapters in our collective history."

The report is the result of a six-year study of Canada's former government policy requiring Canadian Indians to attend the schools, often the scenes of physical and sexual abuse. Indian leaders have cited the legacy of abuse and isolation as the root cause of epidemic substance abuse rates on reservations.

From the 19th century until the 1970s, more than 150,000 aboriginal children were required to attend Christian schools to rid them of their native cultures and integrate them into Canadian society.