Prime Minister Justin Trudeau
© Sean Kilpatrick/The Canadian Press via APCanada Prime Minister Justin Trudeau delivers a statement in the House of Commons on Parliament Hill in Ottawa, Ontario, on Monday, Sept. 18, 2023.
India expelled a senior Canadian diplomat Tuesday and accused Canada of interfering in its internal affairs, escalating a breach with Ottawa over its allegations of Indian involvement in the killing of a Sikh activist in Canada.

It came a day after Canadian Prime Minister Justin Trudeau said there were credible allegations that India was connected to the assassination of Hardeep Singh Nijjar, a Sikh independence advocate who was gunned down on June 18 outside a Sikh cultural center in Surrey, British Columbia, and Canada expelled a top Indian diplomat. India rejected the allegations as "absurd."

India has fought against a movement to establish an independent Sikh homeland known as Khalistan since the 1980s, when a raid on separatists in a major temple led to the assassination of a prime minister and a wave of anti-Sikh violence.

Nijjar was wanted by Indian authorities, who accused the activist of involvement in an alleged attack on a Hindu priest in India and had offered a cash reward for information leading to his arrest. Nijjar was organizing an unofficial referendum on Sikh independence from India at the time of this death.

Gurpatwant Singh Pannun, a lawyer and spokesperson for the Sikhs For Justice organization, has said Nijjar had been warned by Canadian intelligence officials about being targeted for assassination by "mercenaries" before he was gunned down.

Trudeau told Parliament Monday that Canadian security agencies were investigating "credible allegations of a potential link between agents of the government of India and the killing of a Canadian citizen."

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

India's foreign ministry dismissed the allegation as "absurd and motivated," and accused Canada of harboring "terrorists and extremists."

"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 wrote in a statement issued earlier Tuesday.

India has long demanded that Canada take action against the Sikh independence movement, which is banned in India but has support in countries like Canada and the U.K. with sizable Sikh diaspora populations. Canada has a Sikh population of more than 770,000, about 2% of its total population.

In March, the Modi government summoned the Canadian high commissioner in New Delhi, the top diplomat in the country, to complain about Sikh independence protests in Canada. In 2020, India's foreign ministry also summoned the top diplomat over comments made by Trudeau about an agricultural protest movement associated with the state of Punjab, where many Sikhs live.

Critics accuse Modi's Hindu nationalist government of seeking to suppress dissenters and activists using sedition laws and other legal weapons. Some critics of his administration, including intellectuals, activists, filmmakers, students and journalists have been arrested, creating what Modi's opponents say is a culture of intimidation.

The dueling expulsions come amid tense relations between Canada and India. Trade talks have been derailed and Canada just canceled a trade mission to India that was planned for the fall.

Trudeau told Parliament that he brought up Nijjar's slaying with Indian Prime Minister Narendra Modi at the G20 meeting in New Delhi last week. He said he told Modi that any Indian government involvement would be unacceptable and that he asked for cooperation in the investigation.

At the G20 meeting, Modi expressed "strong concerns" over Canada's handling of the Sikh independence movement during a meeting with Trudeau at the G20, India's statement said.

The statement called on Canada to work with India on what New Delhi said is a threat to the Canadian Indian diaspora, and described the Sikh movement as "promoting secessionism and inciting violence" against Indian diplomats. Earlier this year, supporters of the Khalistan movement vandalized Indian consulates in London and San Francisco.

While in New Delhi for the G20, Trudeau skipped a dinner hosted by the Indian president and local media reports said he was snubbed by Modi when he got a quick "pull aside" meeting instead of a bilateral meeting. To make things worse, Trudeau was stuck in India for 36 hours after the summit ended because his flight was grounded due to a mechanical snag. "Trudeau's turbulent India trip refuses to end," read the headline on the India Today website last week.

It's unclear when exactly Trudeau brought up Nijjar's case with Modi during the G20.

Some analysts in India questioned whether Canada had proof of Indian links to the killing, and whether Trudeau was trying to drum up support among the Sikh diaspora.

"Such a charge against India by a G7 nation is unprecedented. The Canadian government has deliberately made a spectacle of it to please its domestic constituency amongst the Sikh diaspora," said K.C. Singh, a former diplomat and strategic affairs expert. He added that Canada didn't present hard evidence and that Trudeau's statement "unnecessarily upped the ante."

"India should've seen it coming. Trudeau needed to be engaged, not snubbed during his India visit. Now it has reached a point of difficult return," Singh, the former diplomat, also remarked on X, formerly known as Twitter.

On Monday Canadian Foreign Minister Mélanie Joly said the expelled Indian diplomat was the head of Indian intelligence in Canada.

Joly said Trudeau also raised the matter with U.S. President Joe Biden and U.K. Prime Minister Rishi Sunak.

"We are deeply concerned about the allegations referenced by Prime Minister Trudeau," White House National Security Council spokesperson Adrienne Watson. "We remain in regular contact with our Canadian partners. It is critical that Canada's investigation proceed and the perpetrators be brought to justice."

Canadian opposition New Democrat leader Jagmeet Singh, who is himself Sikh, called it outrageous and shocking. Singh said he grew up hearing stories that challenging India's record on human rights might prevent you from getting a visa to travel there.

"But to hear the prime minister of Canada corroborate a potential link between a murder of a Canadian citizen on Canadian soil by a foreign government is something I could never have imagined," Singh said.

The World Sikh Organization of Canada called Nijjar an outspoken supporter of Khalistan who "often led peaceful protests against the violation of human rights actively taking place in India and in support of Khalistan."

"Nijjar had publicly spoken of the threat to his life for months and said that he was targeted by Indian intelligence agencies," the statement said.

India's main opposition party issued a statement backing Modi's position. The Congress Party wrote that "the country's interests and concerns must be kept paramount at all times" and that the fight against terrorism has to be uncompromising, especially when it threatens the nation's sovereignty.

In 1984, Indian forces stormed the Golden Temple in the state's Amritsar city to flush out Sikh separatists, who had taken refuge there. The controversial operation killed around 400, according to official figures, although Sikh groups estimate the toll to be higher.

The prime minister who ordered the raid, Indira Gandhi, was killed afterwards by two of her bodyguards, who were Sikh. Her death triggered a series of anti-Sikh riots, in which Hindu mobs went from house to house across northern India, pulling Sikhs from their homes, hacking many to death and burning others alive.