A few hundred members of Canada's Sikh community demonstrated outside the Indian consulate in Toronto on Saturday to protest the unsolved murder of one of their leaders last month in the Vancouver area.

They accused the Indian government of being responsible for the gunning down of Hardeep Singh Nijjar, president of a Sikh temple and campaigner for the creation of an independent Sikh state that supporters hope to call Khalistan.

"When an Indian agency and system commit a crime, they have to be held accountable," Kuljeet Singh, spokesperson for Sikhs for Justice, a US-based organization behind the rally, told AFP.

Nijjar, whom India had declared a wanted terrorist, was gunned down on June 18 in Surrey, a suburb of Vancouver that is home to one of the largest Sikh populations in Canada.

Another protestor, Hakirt Singh, a lawyer, told AFP that the Royal Canadian Mounted Police (RCMP) "should investigate this murder" as a political assassination.

"When there is vandalism against a member of Parliament you see tweets and reactions from politicians. Here it is an assassination of a Canadian citizen on Canadian soil. That is foreign interference."

Nijjar advocated for the creation of an independent Sikh state to be carved out of parts of northern India and perhaps part of Pakistan. India accused Nijjar of carrying out terrorist attacks in India, a charge he denied.

The demonstrators, almost exclusively men, carried yellow flags with blue logos representing their separatist movement, and shouted "Khalistan! Khalistan!"

Setting off from the Toronto suburbs, they arrived in front of the Indian consulate, where they were greeted by around 50 members of the diaspora in support of the Indian government.

"They have a poster here calling to kill Indian diplomats. We are concerned because these groups have committed terrorist acts in the past and politicians are not taking actions," one of the counterdemonstrators, Vijay Jain, an IT consultant, told AFP.

A line of 20 policemen intervened to separate the two groups, and one Sikh protester was taken away after forcing down a barrier and running to the other side.

Since the murder of the Sikh leader, tensions have risen between Canada and India.

New Delhi regularly accuses Ottawa of laxity in its handling of Sikh protesters in Canada.

"We have asked the Canadian government to take all necessary measures to ensure the safety of our diplomats," Arindam Bagchi, spokesman for India's foreign minister, said on Thursday.

Canada is home to the largest number of Sikhs outside their home state of Punjab, India.