OTTAWA, Sept. 18 (Xinhua) -- Canada has expelled a top Indian diplomat for his alleged involvement in the assassination of Canadian Sikh leader Hardeep Singh Nijjar in the Canadian province of British Columbia in June, Foreign Minister Melanie Joly said Monday.

The allegations against the Indian diplomat, she said, are very serious and, if these allegations were proven it would be a great violation of Canada's sovereignty.

"If proven true this would be a great violation of our sovereignty and of the most basic rule of how countries deal with each other," Joly told journalists. "As a consequence we have expelled a top Indian diplomat."

Joly said she "expects India to fully collaborate with us and ultimately to get to the bottom of this."

The foreign minister also said she plans to take up the matter during an evening meeting with G7 foreign ministers in New York on Monday.

Meanwhile, Canada's Prime Minister Justin Trudeau has said that national security agencies are presently investigating "credible allegations" that the "agents of the government of India" could be involved in the killing of prominent Canadian Sikh leader.

"Over the past number of weeks, Canadian security agencies have been actively pursuing credible allegations of a potential link between agents of the government of India and the killing of a Canadian citizen Hardeep Singh Nijjar," Trudeau said while addressing the Canadian House of Commons on Monday.

Nijjar had been a prominent advocate of the Khalistan movement, which seeks to establish an independent homeland for the Sikh community in India's northwestern Punjab region. Nijjar was killed outside the Guru Nanak Sikh Gurdwara temple in Surrey, British Columbia, on June 18.

The Indian Embassy in Ottawa has not immediately reacted to the Canadian government's move. ■