Canadian Prime Minister Justin Trudeau said in September last year there were credible allegations the Indian government was linked to the assassination in his country of Canadian citizen Hardeep Singh Nijjar in June 2023.

India rejected the accusation as "absurd" and at the time told Canada to remove 41 of its 62 diplomats in the country, with relations being tense between the two nations ever since.

Now Canada is expelling six Indian diplomats, including the high commissioner Sanjay Kumar Verma, after police uncovered evidence of ongoing violent criminal activity linked to India's government, according to a senior Canadian government official.

Meanwhile, India has said it ordered the expulsion of six Canadian diplomats - and withdrew Mr Verma - after he and others were named as "persons of interest" in an investigation, but it did not go into detail about the probe.

The Indian foreign ministry said in a statement that "it received a diplomatic communication from Canada yesterday suggesting that the Indian high commissioner and other diplomats are 'persons of interest' in a matter related to an investigation in that country".

It added: "We have no faith in the current Canadian government's commitment to ensure their security. Therefore, the government of India has decided to withdraw the high commissioner and other targeted diplomats and officials."

India's foreign ministry later said it had asked the six Canadian diplomats to leave by this Saturday.

It added that "India reserves the right to take further steps in response to the Trudeau government's support for extremism, violence and separatism against India".

The ministry also said that, in protest, it had summoned the Canadian charge d'affaires Stewart Wheeler, who was told to leave India.

Afterwards, Mr Wheeler reiterated Mr Trudeau's accusation, saying: "Canada has provided credible, irrefutable evidence of ties between agents of the government of India and the murder of a Canadian citizen on Canadian soil.

"Now, it is time for India to live up to what it said it would do and look into those allegations."

India has repeatedly said Canada has not shared any evidence to back its claim about the killing of Mr Nijjar, who had been designated a terrorist by India.

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The Canadian citizen, 45, was shot dead in a car park outside a Sikh temple in Surrey, British Columbia, on 18 June 2023.

He had been a prominent supporter of the Khalistani separatist movement, which wants to establish an independent homeland for Sikhs in India, where they are a minority.

In May this year, Canadian police said a fourth Indian national had been arrested and charged with his murder.

Mr Nijjar was organising an unofficial referendum in India for an independent Sikh nation at the time of this death.

Around 1.8 million people, or more than 5% of the Canadian population, are of Indian heritage.