Hardeep Singh Nijjar was accused of carrying out terrorist attacks in India. (File)
Canada on Monday accused the Indian involvement in the killing of a Khalistani terrorist last June, and expelled New Delhi's intelligence chief in Ottawa in retaliation.
The diplomatic move sent relations between Ottawa and New Delhi, already sour, to a dramatic new low.
Prime Minister Justin Trudeau told an emergency session of the parliamentary opposition at mid-afternoon that his government had "credible allegations" linking Indian agents to the killing of Khalistani terrorist Hardeep Singh Nijjar, in June in British Columbia.
He called "in the strongest possible terms" on the Indian government to cooperate in clearing up the matter.
Foreign Minister Melanie Jolie said the Trudeau government had taken immediate action.
"Today we have expelled a senior Indian diplomat from Canada," she said, without naming the official.
Ms Jolie said the expelled Indian is the head of the Research and Analysis Wing (RAW), India's foreign intelligence agency, in Canada.
Nijjar, whom India had declared a wanted terrorist, was gunned down on June 18 in Surrey, a suburb of Vancouver that is home to a major Sikh community.
He was accused of carrying out terrorist attacks in India.
Tensions between India and Canada have been simmering over the unsolved murder, and Indian unhappiness over how Ottawa has handled the terrorists.
New Delhi accuses Ottawa of turning a blind eye to the activities of Khalistani supporters.
A former adviser to Trudeau, Jocelyn Coulon, asserted that Canada's accusation would have "the effect of a bomb around the world."
India will join "the group of nations that assassinate political opponents" abroad, much as Saudi Arabia orchestrated the murder of journalist Jamal Khashoggi in Turkey in 2018, said Coulon, who is now an independent researcher.
New Delhi did not immediately respond to Canada's charges.
Tensions between the two nations flared further earlier this month during the G20 summit in New Delhi, which Trudeau attended.
Prime Minister Narendra Modi expressed "strong concerns about continuing anti-India activities of extremist elements in Canada" during a meeting with Trudeau, according to a government statement.
Canada recently suspended negotiations for a free trade agreement with India. Trudeau later told media that Canada would always defend "freedom of expression, freedom of conscience and freedom of peaceful protest" while acting against hatred.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)