NEW DELHI, Sep 20 (AFP) - India on Wednesday told its citizens to avoid travelling to parts of Canada, following a diplomatic row sparked by the allegation that New Delhi was involved in the killing of a Sikh separatist near Vancouver.

Canadian Prime Minister Justin Trudeau has demanded India treat with "utmost seriousness" allegations that Indian agents played a role in the June murder of Hardeep Singh Nijjar near a Sikh temple.

The fallout saw tit-for-tat diplomatic expulsions in Ottawa and New Delhi, with India rejecting the accusation as "absurd".

India's foreign ministry said it had concerns for the safety of its citizens in Canada as a result of "politically-condoned hate crimes and criminal violence" in the country.

"Threats have particularly targeted Indian diplomats and sections of the Indian community who oppose the anti-India agenda," a ministry statement said.

"Indian nationals are therefore advised to avoid travelling to regions and potential venues in Canada that have seen such incidents," it added.

"Given the deteriorating security environment in Canada, Indian students in particular are advised to exercise extreme caution and remain vigilant."