Prime Minister Justin Trudeau says national security agencies are investigating credible allegations that the agents of the government of India were involved in the killing of prominent Canadian Sikh leader Hardeep Singh Nijjar in B.C. in June.

Over the past number of weeks, Canadian security agencies have been actively pursuing credible allegations of a potential link between agents of the government of India and the killing of a Canadian citizen Hardeep Singh Nijjar, Trudeau said, addressing the House of Commons about an extremely serious matter, after informing the opposition party leaders.

Canada is a rule of law country, the protection of our citizens in defence of our sovereignty are fundamental. Our top priorities have therefore been one, that our law enforcement and security agencies ensure the continued safety of all Canadians. And two, that all steps be taken to hold perpetrators of this murder to account.

Foreign Affairs Minister Melanie Joly also announced that Canada has expelled a key Indian diplomat and said Canada expects India to fully collaborate with us and ultimately to get to the bottom of this. She also said she plans to raise this issue during an evening meeting with the G7 foreign ministers in New York on Monday.

Nijjar had been a long-time advocate of the Khalistan movement, which calls for an independent homeland for Sikhs in Indias Punjab region. The Sikh leader was gunned out outside the Guru Nanak Sikh Gurdwara in Surrey, B.C., on June 18.

Nijjars death had sparked protests from the Sikh community across Canada, many accusing the Indian government of orchestrating the killing and even going as far as holding posters that refer to Indian diplomats as killers.

Last week, Trudeau was in India attending the G20, where there were signs of diplomatic tensions with Indian Prime Minister Narendra Modi.

Trudeau told the House he personally and directly brought up allegations to Modi when they met. Modis office, meanwhile, said India has strong concerns about continuing anti-India activities of extremist elements in Canada.

Any involvement of a foreign government in the killing of a Canadian citizen on Canadian soil is an unacceptable violation of our sovereignty, Trudeau said.

Relations between Canada and India have been strained for some time, and late last week with little explanation federal Trade Minister Mary Ng postponed a trade mission to India that was slated to take place this fall.

In the strongest possible terms, I continue to urge the Government of India to cooperate with Canada to get to the bottom of this matter. I also expect it to reiterate that its position on extra-judicial operations in another country is clearly and unequivocally in line with international law.

Conservative Leader Pierre Poilievre echoed calls for the Indian government to cooperate with Canadian investigators and offered his condolences to the family of Nijjar.

If these allegations are true, they represent an outrageous affront to Canada, to Canadas sovereignty, he told the House. Our citizens must be safe from extrajudicial killings of all kinds, most of all from foreign governments.

NDP Leader Jagmeet Singh said the shocking news will have deep and devastating impacts to Canadians.

I want to also begin by acknowledging the family of Hardeep Singh Nijjar, the family whos now learning that the loss of their loved one was potentially directly related to Indian government involvement. I spoke with Hardeep Singh Nijjars son and I could hear the pain of that loss in his voice, and I can only imagine how much more painful it is going to be, knowing this potential connection, he said in an emotional speech in the House, during which he briefly spoke in Punjabi.

Singh said growing up Sikh he heard stories of what could happen if you raise concerns about human rights violations in India, such as getting denied a visa or facing violence if you went back. Singh himself was denied a visa to India in 2013, which he says was due to his Sikh advocacy and criticism of Indias human rights record.

Governments around the world are trying to silence you. The Indian government and the Modi government, specifically, is attempting to silence you. But truth cannot be silenced. Justice cannot and will not be silenced, he said.

This news also comes as the federal government has launched a public inquiry into foreign interference in Canada, after a series of allegations earlier this year over alleged Chinese meddling in Canadian democracy. The commissioner of this new inquiry has been instructed to look beyond China, to include other foreign states and non-state actors, and Singh is now calling for this specific situation to come under scrutiny as part of this probe.

We need to know the truth. We need to know all potential links, and anyone and everyone responsible should be brought to justice using the full power of a democratic nation, the NDP leader said.

Monday also marks the first day on the job for Quebec Court of Appeal Justice Marie-Josée Hogue, who begins her work as the commissioner leading the public inquiry. Intergovernmental Affairs Minister Dominic LeBlanc told reporters in Ottawa the issue of foreign interference was never the unique purview of one country.

We assume that (Hogue) and the security agencies will do whats necessary for her inquiry to also look at the ways that India interferes in Canada. It was always contemplated in the terms of reference, LeBlanc said.