In a significant escalation of diplomatic tensions, the Canadian government has designated Indian High Commissioner Sanjay Kumar Verma and several other diplomats as “persons of interest” in the investigation into the assassination of Hardeep Singh Nijjar, a Sikh leader and Canadian citizen.

Hardeep Singh Nijjar, who was an outspoken proponent of Khalistan, was shot and killed on June 18, 2023, outside the Guru Nanak Sikh Gurdwara in Newton, Surrey, British Columbia.

His body was found inside his vehicle parked in the 7000-block of Scott Road. In the aftermath of the incident, Canadian law enforcement arrested four individuals of Punjabi-Indian descent, charging them with Nijjar’s murder.

New Delhi rejected the “preposterous imputations” of the Canadian claim, saying it was part of Canadian Prime Minister Justin Trudeau’s “political agenda” centred around “vote bank politics”.

Relations between New Delhi and Ottawa have been frosty since September 2023, when Trudeau said that Canada had credible evidence linking Indian agents to the assassination of a Sikh separatist leader that year, prompting a strong reaction from New Delhi, which denied the allegation.

India has repeatedly said Canada has not shared any evidence to back its claim. India’s foreign ministry said it had received a diplomatic communication from Canada on Sunday, but the statement did not mention any details about the investigation.

“This latest step follows interactions that have again seen assertions without any facts. This leaves little doubt that on the pretext of an investigation, there is a deliberate strategy of smearing India for political gains,” it said.

“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 also alleged that the Trudeau government “has consciously provided space to violent extremists and terrorists to harass, threaten and intimidate Indian diplomats and community leaders in Canada”.

Canada pulled out more than 40 diplomats from India in October 2023 after New Delhi asked Ottawa to reduce its diplomatic presence.

In June, a committee of Canadian parliamentarians had named India and China as the main foreign threats to its democratic institutions, based on input from intelligence agencies.

India’s envoy in Ottawa, Sanjay Kumar Verma, called the report politically motivated and influenced by Sikh separatist campaigners.

Earlier this year, Trudeau said that he hoped India would “engage with us so that we can get to the bottom of this very serious matter”.

Soon after Canada’s allegation, the US claimed that Indian agents were involved in an attempted assassination plot of another Sikh separatist leader in New York in 2023, and said it had indicted an Indian national who was working at the behest of an unnamed Indian government official.

Unlike its angry response to Canadian allegations, however, India expressed concern after the US raised the issue, dissociating itself from the plot, and has launched an investigation.

The assassination plots against Sikh separatist leaders in Canada and the US have tested their relationship with India, as the Western nations hope to forge deeper ties with New Delhi to counter China’s rising global influence.