India has stopped issuing visas to Canadian citizens amid an escalating row over the killing of a Sikh separatist on Canadian soil.
India said the temporary move was due to "security threats" disrupting work at its missions in Canada.
Tensions flared this week after Prime Minister Justin Trudeau said India may have been behind the 18 June killing.
But Mr Trudeau said on Thursday he was not looking to provoke India with the allegation.
India has angrily rejected the allegation, calling it "absurd".
Speaking to reporters in New York, on the sidelines of the UN General Assembly, Mr Trudeau said: "There is no question that India is a country of growing importance and a country we need to continue to work with."
He said Canada was not looking to provoke India or cause problems with the allegation but is unequivocal about the importance of the rule of law and protecting Canadians.
Relations between the countries – key trade and security partners, and US allies – have been strained for months. Analysts say they are now at an all-time low.
India's government swiftly made clear the suspension of visa services also "applies to Canadians in a third country".
"There have been threats made to our high commission [embassy] and consulates in Canada," a foreign affairs ministry spokesman in Delhi said. "This has disrupted their normal functioning. Accordingly [they] are temporarily unable to process visa applications."
He said: "India is looking for parity in rank and diplomatic strength between the diplomatic missions of the two countries. This is being sought because of Canadian diplomatic interference in our internal affairs."
Hours earlier Canada had announced it was reducing its personnel in India, saying some diplomats had received threats on social media.
"In light of the current environment where tensions have heightened, we are taking action to ensure the safety of our diplomats," a statement said.
Canada's visa services remain open in India.
The two countries have historic close ties – and much is at stake.
Canada has 1.4 million people of Indian origin – more than half of them Sikhs – making up 3.7% of the country's population, according to the 2021 census. India also sends the highest number of international students to Canada – in 2022, they made up 40% of total overseas students at 320,000.
According to Indian government statistics, about 80,000 Canadian tourists visited India in 2021, behind only the US, Bangladesh and UK.
The row burst into the open on Monday after Canada linked India with the murder of separatist leader Hardeep Singh Nijjar, a Canadian citizen who was shot dead in his vehicle by two masked gunmen outside a Sikh temple in British Columbia.
Prime Minister Justin Trudeau said Canada's intelligence agencies were investigating whether "agents of the government of India" were involved in the killing of Nijjar – who India designated a terrorist in 2020.
India reacted strongly, saying Canada was trying to "shift the focus from Khalistani terrorists and extremists" who had been given shelter there. The Indian government has often reacted sharply to demands by Sikh separatists in Western countries for Khalistan, or a separate Sikh homeland.
On Thursday, Mr Trudeau was pressed by journalists about what evidence there was that suggested India was linked to the murder.
He did not share further details, but said "the decision to share these allegations was not done lightly".
"It was done with the utmost seriousness," Mr Trudeau said, urging Indian officials to cooperate with the investigation into the killing.
A spokesperson for the Indian foreign ministry said Canada has not shared specific information with India on Nijjar's murder.
"We have conveyed this to the Canadian side, made it clear to them that we are willing to look at any specific information that is provided to us," said Arindam Bagchi on Thursday. "But so far we have not received any such specific information."
The Khalistan movement peaked in India in the 1980s with a violent insurgency centred in Sikh-majority Punjab state.
It was quelled by force and has little resonance in India now, but is still popular among some in the Sikh diaspora in countries such as Canada, Australia and the UK.
BBC News India is now on YouTube. Click here to subscribe and watch our documentaries, explainers and features.
Sign up for our morning newsletter and get BBC News in your inbox.
Israel says military preparing to attack Gaza by 'air, sea and land'
How BBC verified video of Palestinians killed fleeing Gaza
Trump-backed Jim Jordan chosen as Speaker nominee
How Disney took over the world
'I'm totally helpless' – husband of new mother missing after attacks
Worry in UK as Israel-Gaza anxiety spreads
China's roads win hearts in S Asia – but at a cost
How TikTok is hoping to shake up the games industry
Your pictures on the theme of 'texture'
Violin novice to TV orchestra triumph in four years
The 2,500-year-old sport that still flourishes in India. Video
Gaza Strip in maps: What it's like for the people who live there
Europe's unlikely digital nomad hub
Scorsese on finding his new star
The sneaky trend hurting finances
© 2023 BBC. The BBC is not responsible for the content of external sites. Read about our approach to external linking.