TORONTO: Canada and India have expelled a senior diplomat each after Canadian Prime Minister Justin Trudeau alleged the involvement of "agents of the Indian government" in the killing of a prominent Sikh separatist leader in Surrey in June, claims outrightly rejected by New Delhi as "absurd" and "motivated".

Hardeep Singh Nijjar, 45, the chief of the banned Khalistan Tiger Force (KTF) and one of India's most-wanted terrorists who carried a cash reward of Rs 10 lakh on his head, was shot dead by two unidentified gunmen outside a gurdwara in Surrey in the western Canadian province of British Columbia on June 18.

"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 Monday in a speech to the House of Commons.

After Trudeau's remarks in Parliament, Canadian Foreign Minister Melanie Joly confirmed that she has ordered the expulsion of "a senior Indian diplomat."

Reacting sharply to the allegations and Joly's remarks, India on Tuesday rejected Trudeau's claims, calling them "absurd and motivated".

The Ministry of External Affairs (MEA) has also asked a Canadian diplomat to leave India within the next five days.

"Allegations of the Government of India's involvement in any act of violence in Canada are absurd and motivated," the MEA said in a statement on Tuesday in New Delhi.

"Similar allegations were made by the Canadian Prime Minister to our Prime Minister, and were completely rejected," it said.

"We are a democratic polity with a strong commitment to the rule of law," the MEA said.

"Such unsubstantiated allegations seek to shift the focus from Khalistani terrorists and extremists, who have been provided shelter in Canada and continue to threaten India's sovereignty and territorial integrity," it said.

"The inaction of the Canadian Government on this matter has been a long-standing and continuing concern," the ministry said.

The MEA said Canadian political figures have openly expressed sympathy for such elements remains a matter of deep concern.

"The space given in Canada to a range of illegal activities including murders, human trafficking and organised crime is not new," the MEA said.

"We reject any attempts to connect the Government of India to such developments," it said.

"We urge the Government of Canada to take prompt and effective legal action against all anti-India elements operating from their soil," it added.

Hours later, Trudeau said he was not looking to "provoke" India or "escalate" tensions, but urged New Delhi to take the killing of a Sikh separatist leader with the "utmost seriousness".

He said the Indian government needs to "take this matter with the utmost seriousness.

"We are doing that. We are not looking to provoke or escalate," he told reporters.

"We want to work with the government of India to lay everything clear and to ensure there are proper processes." In his speech in Parliament on Monday, Trudeau told the lawmakers that any involvement of a foreign government in killing a Canadian citizen on Canadian soil is an unacceptable violation of our sovereignty.

"It is contrary to the fundamental rules by which free, open and democratic societies conduct themselves," he said.

"As you would expect, we have been working closely and coordinating with our allies on this very serious matter," he added.

He also said that he had raised with Prime Minister Narendra Modi the issue during their meeting on the sidelines of the G20 summit in New Delhi earlier this month.

Trudeau urged the Indian government to cooperate with Canada to get to the bottom of this matter.

During the bilateral meeting with Trudeau on September 10, Prime Minister Modi conveyed India's strong concerns about continuing anti-India activities of extremist elements in Canada as they are promoting secessionism, inciting violence against Indian diplomats and threatening the Indian community there.

The Canadian foreign minister's office identified the expelled Indian diplomat as Pavan Kumar Rai, the head of India's foreign intelligence agency in Canada, the Toronto Star newspaper reported.

"My expectations are clear. I expect India to fully collaborate with us and get to the bottom of this," Joly said.

Citing a senior government source, CBC News reported that Trudeau has briefed the leaders of some of Canada's closest allies about the case, including US President Joe Biden, British Prime Minister Rishi Sunak and French President Emmanuel Macron.

In Washington, the White House said it was "deeply concerned" about the allegations raised by Trudeau.

"We remain in regular contact with our Canadian partners. It is critical that Canada's investigation proceed and the perpetrators be brought to justice," National Security Council spokesperson Adrienne Watson said in a statement.

Reacting to the incident, a State Department spokesperson said, "We are deeply concerned about the allegations referenced by PM Trudeau yesterday. We remain in regular contact with our Canadian partners. It is critical that Canada's investigation proceed and the perpetrators be brought to justice. We urge the Indian government to cooperate in the Canadian investigation and ensure that those responsible are held to account."

In London, a UK government spokesperson said that Britain was in "close touch with our Canadian partners about these serious allegations.

Prime Minister Rishi Sunak's spokesperson at 10 Downing Street was asked about the impact the issue may have on India-UK relations.

"We are in close touch with our Canadian partners about these serious allegations," the spokesperson said.

"It would be inappropriate to comment further during the ongoing investigation by the Canadian authorities."

 Later, when Sunak's spokesperson was pressed on the matter, he said work on the trade negotiations with India "continue as before".

A spokesperson for Australian Foreign Minister Penny Wong said Canberra was "deeply concerned" by the allegations made by Canada.

"We have conveyed our concerns at senior levels to India," the spokesperson said.

"The Indian diaspora are valued and important contributors to our vibrant and resilient multicultural society, where all Australians can peacefully and safely express their views," the spokesperson was quoted as saying by The Sydney Morning Herald.

Public Safety Minister Dominic LeBlanc said the Royal Canadian Mounted Police (RCMP) is leading the murder investigation.

"We'll hold the perpetrators accountable and bring them to justice," he said.

Canadian police have not arrested anyone in connection with Nijjar's killing.

Last month, police released a statement saying they were investigating three suspects.

Canada-based Nijjar was designated a 'terrorist' by India under the stringent Unlawful Activities (Prevention) Act in July 2020 and his property in the country was attached by the National Investigation Agency (NIA) in September 2020.

Interpol Red Corner Notice was also issued against him in 2016.

The local police of Surrey had also put Nijjar under house arrest temporarily in 2018 on suspicion of his terror involvement but he was released later.

Bilateral ties between India and Canada have been tense in recent months. Trade talks have been derailed and Canada just cancelled trade talks.

Last week, a senior official said in New Delhi that negotiations for a free trade agreement between India and Canada will resume after the resolution of political issues between the two countries.

Meanwhile, the son of Nijjar, Balraj Nijjar, on Monday said the loss of his father is still fresh, especially given the circumstances of his death.

"It's been hard, obviously. You generally don't expect something like this to happen even in terms of age, because he's only 45,"  Balraj was quoted as saying by Vancouver-based Global News.

It also reported that Sikh community members vowed Monday to protest in front of the Indian consulates across Canada following Trudeau's statement.

Canada has a Sikh population of more than 770,000 (about 2 per cent of its total population).