India and Canada on Monday expelled each other's senior-most diplomats after Ottawa named Indian high commissioner Sanjay Kumar Verma and other diplomats and officials as "persons of interest" in the investigation into the assassination of Khalistani activist H.S. Nijjar on Canadian soil.

The day's developments, which have plunged bilateral ties to an all-time low, began with India announcing in the evening that it would withdraw Verma and the others named by Canada.

Later at night, New Delhi announced the expulsion of six Canadian diplomats including chargé d'affaires Stewart Wheeler and deputy high commissioner Patrick Hebert. The other four expelled diplomats are all in the rank of first secretary. They have been asked to leave India by 11.59pm on Saturday.

The Washington Post later reported that Canada had ordered six Indian diplomats "directly involved in gathering detailed intelligence of Sikh separatists who were then killed, attacked or threatened by India’s criminal proxies" to leave the country. Reuters confirmed the expulsions by Canada.

On Tuesday, an Indian inquiry committee, probing US allegations of an Indian government official’s involvement in a foiled plot to assassinate American national and Sikh separatist Gurpatwant Singh Pannun, is expected to arrive in Washington, PTI reported.

The external affairs ministry had announced the decision to withdraw Verma and the others after Secretary (East) Jaideep Mazumdar summoned Wheeler.

The Canadian was informed that "the baseless targeting of the Indian high commissioner and other diplomats and officials in Canada was completely unacceptable" and that they were being withdrawn as New Delhi had "no faith in the current Canadian government’s commitment to ensure their safety".

Leaving South Block after the meeting, Wheeler told reporters that “Canada has done what India has long been asking for” in relation to the murder of Hardeep Singh Nijjar in June last year.

“Canada has provided credible, irrefutable evidence of ties between the agents of the Government of India and the murder of a Canadian citizen on Canadian soil,” Wheeler said.

“Now it is time for India to live up to what it said it would do and look into those allegations. It is in the interest of both our countries, and the people of both our countries, to get to the bottom of this. Canada stands ready to cooperate with India.”

Wheeler had been summoned after India on Sunday received a diplomatic communication from Canada that named Verma and some other diplomats and officials as “persons of interest” in the Nijjar investigation.

Given the time difference between India and Canada, there was no immediate response from Ottawa, barring Stewart’s comments, to New Delhi’s act of publicising the Canadian diplomatic communication and its decision to withdraw diplomats and officials.

In the afternoon, the external affairs ministry had rejected “these preposterous imputations” from Canada and ascribed them to “the political agenda of the (Justin) Trudeau government that is centred around vote bank politics”.

“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,” the ministry had said in a statement.

After the meeting with Wheeler, the tenor became sharper: “India reserves the right to take further steps in response to the Trudeau government’s support for extremism, violence and separatism against India.”

The Indian statement did not mention Nijjar but contained enough indication that the issue at hand was his assassination.

Prime Minister Trudeau had in the House of Commons last year alleged an Indian hand in Nijjar’s murder, a charge New Delhi denies. However, other Western capitals have indicated that Trudeau made this statement based on information shared within the “Five Eyes” intelligence alliance of the US, UK, Canada, Australia and New Zealand.

The external affairs ministry said that despite many requests from India, the Canadian government had not shared a shred of evidence with it since Trudeau aired the allegation.

“This latest step follows interactions that have again witnessed 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.

The ministry statement backed Verma personally, underlining that he was the country’s senior-most serving diplomat with a distinguished career of 36 years that included two ambassadorial posts in Japan and Sudan.

“The aspersions cast on him by the Government of Canada are ludicrous and deserve to be treated with contempt,” the statement said.

It said New Delhi had taken cognisance of the Canadian high commission’s activities in India that served the political agenda of the current government in Ottawa.

The statement dwelt on India’s troubled relationship with Trudeau, going back to his India visit in 2018 “which was aimed at currying favour with a vote bank”.

It said Trudeau’s hostility to India had long been in evidence, and asserted that his cabinet had included individuals who had openly associated with an extremist and separatist agenda relating to India.

“His naked interference in Indian internal politics in December 2020 showed how far he was willing to go in this regard,” it said, alluding to the Canadian Premier’s comments on the farmer protests.

“That his government was dependent on a political party whose leader openly espouses a separatist ideology vis-à-vis India only aggravated matters.”

The New Democratic Party of Jagmeet Singh withdrew support to Trudeau’s Liberal Party in September this year.

“Under criticism for turning a blind eye to foreign interference in Canadian politics, his government has deliberately brought in India in an attempt to mitigate the damage,” the ministry statement said.

“This latest development targeting Indian diplomats is now the next step in that direction. It is no coincidence that it takes place as Prime Minister Trudeau is to depose before a commission on foreign interference. It also serves the anti-India separatist agenda that the Trudeau government has constantly pandered to for narrow political gains.”

The statement added that Trudeau’s government had consciously provided space to violent extremists and terrorists to harass, threaten and intimidate Indian diplomats and community leaders in Canada.

“This has included death threats to them and to Indian leaders. All these activities have been justified in the name of freedom of speech,” the statement said.

“Some individuals who have entered Canada illegally have been fast-tracked for citizenship. Multiple extradition requests from the Government of India in respect of terrorists and organised crime leaders living in Canada have been disregarded.”

Trudeau’s approval ratings are dipping in Canada amid predictions that the Conservatives will win next year’s federal elections.

Reports in the Canadian media have over the past couple of days described efforts by some Liberal Party members to have Trudeau replaced after the party suffered successive defeats in safe seats over the past three months.

On the arrival of the Indian committee probing the foiled Pannun assassination, a US government release said: “The enquiry committee will be travelling to Washington, DC, on October 15th, as part of their ongoing investigations to discuss the case, including information they have obtained, and to receive an update from US authorities regarding the US case that is proceeding.”

India had established the committee to probe the activities of certain organised criminals. The committee is now investigating the Pannun murder plot.

US federal prosecutors had last November charged Indian national Nikhil Gupta with working with an Indian government employee on a foiled plot to kill Pannun in New York City. Gupta, arrested in the Czech Republic in June last year, was extradited to the US on June 14.

India has denied the allegation.

Additional reporting by PTI