India, Jan. 15 -- India's High Commissioner to Canada, Dinesh Patnaik, has delivered one of the strongest public rebukes yet of Ottawa's handling of extremist groups, accusing Canadian authorities of failing for nearly four decades to effectively act against terrorism operating within the country.

In a tense interview with Canada's public broadcaster CBC on Tuesday, Patnaik said prolonged inaction by Canadian institutions had allowed extremist networks to function with impunity, creating security risks that have directly impacted India.

The discussion, held against the backdrop of British Columbia Premier David Eby's trade visit to India and early signals from Ottawa about improving bilateral ties, quickly shifted from economic cooperat...