TORONTO (AP) — India has told Canada to remove 41 of its 62 diplomats in the country, an official familiar with the matter said Tuesday, ramping up a confrontation between the two countries over Canadian accusations that India may have been involved in the killing of a Sikh separatist leader in suburban Vancouver.

The official spoke on condition of anonymity because they were not authorized to speak publicly ahead of public reaction from the Canadian government later Tuesday. The official confirmed an earlier report from the Financial Times.

India’s Ministry of External Affairs declined to comment, but ministry spokesperson Arindam Bagchi had previously called for a reduction in Canadian diplomats in India, saying they outnumbered India’s staffing in Canada.

Canadian Prime Minister Justin Trudeau stood up in Parliament last month and said there were “credible allegations” of Indian involvement in the slaying of Hardeep Singh Nijjar, a 45-year-old Sikh leader who was killed by masked gunmen in June in Surrey, outside Vancouver. For years, India has said Nijjar, a Canadian citizen born in India, has links to terrorism, an allegation Nijjar denied.

Arranging the killing of a Canadian citizen in Canada, home to nearly 2 million people of Indian descent, would be unprecedented.

On Tuesday, Trudeau didn’t confirm the number of diplomats that have been told to leave but suggested Canada would not retaliate.

“Obviously, we are going through an extremely challenging time with India right now, but that’s why it is so important for us to have diplomats on the ground working with the Indian government and there to support Canadians and Canadian families,” Trudeau said. “We’re taking this extremely seriously, but we’re going to continue to engage responsibly and constructively with the Indian government.”

India has accused Canada for years of giving free rein to Sikh separatists, including Nijjar.

India has also canceled visas for Canadians. Canada has not retaliated for that. India previously expelled a senior Canadian diplomat after Canada expelled a senior Indian diplomat.

Trudeau has also previously appeared to try to calm the diplomatic clash, telling reporters that Canada is “not looking to provoke or escalate.”

The allegation of India’s involvement in the killing is based in part on the surveillance of Indian diplomats in Canada, including intelligence provided by a major ally, a separate Canadian official previously told The Associated Press.

The official said that the communications involved Indian officials and diplomats in Canada and that some of the intelligence was provided by a member of the “Five Eyes” intelligence-sharing alliance, which includes the United States, Britain, Australia and New Zealand, in addition to Canada. The official spoke on condition of anonymity because they were not authorized to discuss the matter publicly.

The latest expulsions by India have escalated tensions between the countries. Trudeau had frosty encounters with Indian Prime Minister Narendra Modi during this month’s Group of 20 meeting in New Delhi, and a few days later, Canada canceled a trade mission to India planned for the fall.

“This is a clear show of force on the part of the Modi government, who’s not afraid to escalate this diplomatic crisis,” said Daniel Béland, a political science professor at McGill University in Montreal. “It’s a dramatic move that seriously weakens the capacity of Canada’s diplomatic services in India. ”

Béland said it will hurt many Indian citizens, including the many Indian foreign students and temporary foreign workers in need of a Canadian visa.

“The U.S. needs to do more to solve this diplomatic crisis,” he said.

U.S. Secretary of State Antony Blinken met last week with India’s foreign minister amid the simmering row between New Delhi and Ottawa. A U.S. official said the topic was raised.

U.S. officials have acknowledged that the fallout from the allegations, which they take seriously, could have a profound impact on relations with India, but have been careful not to cast blame in the killing of Nijjar.

There is a priority among the allies to bolster ties with India as a counterweight to Beijing’s rising power and assertiveness.

“Reality is we need to find pathways of de-escalation, and perhaps Canada’s allies can be helpful here,” said Bruce Heyman, a U.S. ambassador to Canada during the Obama administration.

“The West is working hard at building strong alliances against authoritarian rule. President Biden and his team have invested diplomatically in the India relationship. India is an important part of the alliance-building taking place. This isn’t about either/or, but finding pathways to de-escalation among allies and friends,” Heyman said.

Maitreyi Bhatt, a 27-year-old Indian citizen in Toronto whose partner is Canadian and needs a visa, remains distraught because her wedding was scheduled to take place in India in late October, when he was to meet her family for the first time. She said the venue was booked and the couple has nonrefundable flights

“It’s still in limbo. The way the situation is accelerating, I don’t see them coming to a solution to this anytime soon,” she said. “It just feels super weird. I never thought I would be a part of this, but sadly I am.”

Nijjar, a plumber, was also a leader in what remains of a once-strong movement to create an independent Sikh homeland, known as Khalistan. A bloody decadelong Sikh insurgency shook north India in the 1970s and 1980s, until it was crushed in a government crackdown in which thousands of people were killed, including prominent Sikh leaders.

The Khalistan movement has lost much of its political power but still has supporters in the Indian state of Punjab, as well as in the sizable overseas Sikh diaspora. While the active insurgency ended years ago, the Indian government has warned repeatedly that Sikh separatists were trying to make a comeback.