Canada on Sunday updated its travel advisory for India to include warnings about protests and “negative sentiments” towards the country on social media in the wake of a diplomatic crisis over the killing of a Sikh separatist leader.

“Please remain vigilant and exercise caution,” the advisory read.

A week ago, Canadian Prime Minister Justin Trudeau had told the country’s parliament that its intelligence agencies were actively pursuing “credible allegations” tying Indian agents to the shooting of Hardeep Singh Nijjar, a 45-year-old Sikh separatist leader. Nijjar, a Canadian citizen, was killed by masked gunmen on June 18 in Surrey, outside Vancouver.

India had quickly rejected the charges as “absurd and motivated”. It also warned its citizens in Canada and those planning to travel to the North American country to be cautious because of “growing anti-India activities and politically condoned hate-crimes”.

Canada’s accusations have sparked tit-for-tat retaliation, with each country expelling diplomats. India has also indefinitely suspended visa services in Canada, citing security threats to its officials.

But Trudeau reiterated that Ottawa had “credible reasons” to believe that New Delhi was behind Nijjar’s assassination. The decision to go public with the allegations, he added, “was not done lightly”.

On Saturday, United States Ambassador to Canada David Cohen confirmed that information shared by members of an intelligence-sharing alliance had informed Trudeau of the Indian government’s possible involvement in the killing of Nijjar.

“There was shared intelligence among ‘Five Eyes’ partners that helped lead Canada to [make] the statements that the prime minister made,” Cohen told CTV News in an interview.

The Five Eyes alliance consists of the United States, the United Kingdom, Australia, New Zealand and Canada.

The United States has asked India to cooperate with the investigation in the case. “We want to see accountability,” said Secretary of State Antony Blinken, who is the most senior official in Washington to have commented on the matter so far.