Diplomatic ties between India and Canada sank to a new low on Monday as each expelled six diplomats in tit-for-tat moves in an escalating dispute over the killing of a Canadian Sikh activist in Vancouver last year.

Canada has alleged that agents linked to the Indian government were involved in the killing of Hardeep Singh Nijjar, a Canadian citizen and prominent campaigner for a sovereign Sikh state — known as Khalistan — in northern India.

The Royal Canadian Mounted Police (RCMP) on Monday identified India's envoy as a "person of interest" in its investigation, and Canada's Foreign Ministry asked the diplomat and five others to leave the country. India soon responded in kind.

Trudeau: 'India has made fundamental error'

Canadian Prime Minister Justin Trudeau said on Monday evening that India had "made a fundamental error in choosing to use their diplomats and organized crime to attack Canadians."

"As the RCMP commissioner stated earlier, they have clear and compelling evidence that agents of the government of India have engaged in and continue to engage in activities that pose a significant threat to public safety," Prime Minister Justin Trudeau said after the news of the diplomats being sent home.  

"This includes clandestine information gathering techniques, coercive behavior targeting South Asian Canadians, and involvement in over a dozen threatening and violent acts, including murder. This is unacceptable," Trudeau said. 

He added: "Canada is a country rooted in the rule of law and the protection of our citizens is paramount. We will never tolerate the involvement of a foreign government threatening and killing Canadian citizens on Canadian soil."

Canadian police have charged multiple Indian nationals in Nijjar's murder. 

What does Canada allege?

The Royal Canadian Mounted Police (RCMP) issued a statement earlier on Monday on the case .

It said it had identified four "very serious issues" during its probe.

These included violent extremism impacting both countries, "links tying agents of the Government of India to homicides and violent acts," using organized crime to create "a perception of an unsafe environment targeting the South Asian community in Canada," and "interference into democratic processes." 

Police said that despite law enforcement action during their investigation, "the harm has continued, posing a serious threat to public safety." 

"We reached a point where we felt it was imperative to confront the Government of India and inform the public about some very serious findings that have been uncovered through our investigations," the RCMP said.

India slams 'preposterous' Canadian claims

After receiving the message suggesting that India's envoy to Ottawa and five other diplomats were "persons of interest" in the Canadian investigation, New Delhi rejected the claims as "preposterous."

It says it has repeatedly asked Canada for more explicit evidence, which it says has not been provided, and has accused Canada of making false allegations for political reasons.

Canada, meanwhile, accuses India of refusing to cooperate with its investigations.

"India now reserves the right to take further steps in response to these latest efforts of the Canadian Government to concoct allegations against Indian diplomats," it said, before expelling Canada's acting high commissioner, deputy high commissioner and four other diplomats, saying that they were to leave India by the end of Saturday.

Last October, dozens of Canadian diplomats left India after New Delhi threatened to revoke their diplomatic immunity. This followed the Canadian government making its investigation of the case and its suspicion of Indian government involvement public.

Stern strain on bilateral ties

India and Canada have historically shared warm ties, and the two countries have been key strategic partners on issues like trade and security.

But relations have been strained ever since Prime Minister Trudeau accused Indian government agents of being involved in the killing of Nijjar — a wanted man in India but who had arrived in Canada decades ago and had obtained Canadian citizenship.

Canada is home to the world's largest Sikh population outside the sub-continent with Sikhs making up around 2% of the population. But India has long seen Sikh separatists abroad as a security threat.

In a separate case south of the Canadian border, US prosecutors have accused an Indian government agent of directing an unsuccessful plot to assassinate Gurpatwant Singh Pannun, an American citizen who advocated for Khalistan.

mf,rm/msh (Reuters, AFP)