India on Tuesday trashed Canada's attempts to link Indian agents with criminal gangs in that country with official sources rejecting Ottawa's claim that it shared evidence with New Delhi in the Nijjar case.

The sources also rejected Canadian Prime Minister Justin Trudeau's allegations that India was engaging in activities, including carrying out covert operations targeting Canadian nationals in his country.

The ties between India and Canada witnessed a major downturn on Monday as India expelled six Canadian diplomats and announced withdrawing its High Commissioner from Canada after dismissing Ottawa's allegations linking the envoy to a probe into the killing of Sikh extremist Hardeep Singh Nijjar.

"Canadian PM Trudeau's press conference yesterday was the same old Trudeau saying the same old things for the same old reasons," said a source.

The sources said the assertions by Canadian officials that Canada presented credible evidence to India in the Nijjar case is simply not true.

"The central assertion from all Canadian officials is that credible evidence has been presented to India. This was also repeated by their Charge d'Affaires Stewart Wheelers to the press. This is simply not true," the source said.

"From the very beginning, the Canadian approach has been to make vague accusations and put the burden of denial on India," it added.

The sources also rejected attempts by the Royal Canadian Mounted Police (RCMP) to link Indian agents to the Bishnoi gang.

At the RCMP press briefing, assertions were made about connections of certain individuals to India. In no case were any specifics provided, the sources said.

There was also talk about holding people accountable. But it was never made clear who and for what, they said.

The sources also slammed Canada for targeting the Indian high commissioner to Ottawa.

It is absurd that after intensively engaging the High Commissioner over the last year, the Canadian government now chooses to target him, they said.