Canada is "adjusting" its diplomatic presence in India as Delhi suspends visas for Canadian citizens.
It is part of an escalating row over the killing of Sikh leader Hardeep Singh Nijjar in the Canadian province of British Columbia earlier this year.
Justin Trudeau, the Canadian prime minister, said his country is "not looking to provoke or cause problems".
Speaking on the sidelines of the UN General Assembly in New York, however, he added that Canada is "unequivocal around the importance of the rule of law".
He told parliament on Monday there are "credible allegations" India was involved in the killing of Mr Nijjar, a Sikh independence activist.
India's visa processing centre in Canada responded on Thursday by suspending visas for "operational reasons" - but gave no further details.
This notice was taken down minutes later by BLS International, an Indian company that provides visa services, before reappearing again on Thursday morning.
India's foreign ministry spokesperson did not respond to questions on the matter.
Canada's high commission, meanwhile, said its diplomats in India have received threats on social media, adding it will temporarily adjust staff presence in the country, according to news agency ANI.
The country also expelled an Indian diplomat, while India expelled a Canadian diplomat on Tuesday.
India has dismissed allegations that it was linked to the killing of Mr Nijjar in Canada earlier this year as "absurd".
The Canadian citizen was shot dead outside a Sikh temple in Surrey, British Columbia, on 18 June.
He was one of the key members of the Khalistan movement - and was in the process of organising an unofficial referendum on its proposed independent Sikh state when he died.
On Wednesday, India updated its travel advisory for Canada, urging citizens in Canada to be cautious of "growing anti-India activities and politically condoned hate crimes".
Venues in Canada where "threats have particularly targeted Indian diplomats and sections of the Indian community who oppose anti-India agenda" should also be avoided, India said.