Canadian Prime Minister Justin Trudeau says the Indian government could be behind the fatal shooting of Canadian Sikh leader Hardeep Singh Nijjar.

Speaking in Canadian Parliament, he said Canadian intelligence has identified a credible link between his death and the Indian state.

Canadian Prime Minister said he raised the issue with Indian Prime Minister Narendra Modi at the recent G20 summit.

He said any involvement of a foreign government in the killing of a Canadian citizen is an unacceptable violation of Canadian sovereignty.

Canadian Prime Minister said Canada has declared its deep concerns to the top intelligence and security officials of the Indian government.

Hardeep Singh Nijjar, was shot dead outside a Sikh temple in Surrey, British Columbia, on June 18.

Meanwhile, Canada has expelled a top Indian diplomat as it investigates what Prime Minister Justin Trudeau called credible allegations that Indian government have had links to the assassination of a Sikh activist Hardeep Singh in Canada.

Canadian Foreign Minister Mélanie Joly said the head of Indian intelligence in Canada has been expelled as a consequence.