Canada has expelled six Indian diplomats and consular officials in relation to an investigation of the murder of a Sikh separatist leader in British Columbia last year, the foreign ministry said on Monday.

India earlier said it had ordered the expulsion of six top Canadian diplomats, including the acting high commissioner, and said it had withdrawn its envoy from Canada, contradicting Canada's statement that it had expelled the envoy.

Relations between the two countries have been fraught since last year, when Canadian Prime Minister Justin Trudeau said he had evidence linking Indian agents to the assassination of a Sikh separatist leader in his country.

The Royal Canadian Mounted Police said they had significant information on broad criminal activity orchestrated by agents of the government of India and used to target members of the South Asian community in Canada.

June 18, 2023: Hardeep Singh Nijjar, 45, is shot dead outside a Sikh temple in Surrey, a Vancouver suburb with a large Sikh population. He was a Canadian citizen campaigning for the creation of an independent Sikh homeland carved out of India.

Sept. 1, 2023: A Canadian trade official says Canada paused talks on a proposed trade treaty with India, an unexpected move that came about three months after both countries said they planned to seal an initial pact in 2023.

Sept. 10, 2023: Indian Prime Minister Narendra Modi conveys strong concerns about Sikh separatist protests in Canada to Prime Minister Trudeau on the sidelines of a G20 summit in New Delhi.

Sept. 18, 2023: Trudeau tells parliament that Canada was "actively pursuing credible allegations" linking Indian government agents to Nijjar's killing.

Sept. 19, 2023: India dismisses Trudeau's assertion as "absurd." Each country expels a diplomat in tit-for-tat moves, with Canada throwing out India's top intelligence officer in the country while India expelled his Canadian counterpart.

Sept. 22, 2023: India suspends issuing new visas for Canadians and asks Ottawa to reduce its diplomatic presence in India. India resumes issuing visas two months later.

Oct. 19, 2023: Canada has withdrawn 41 diplomats from India amid a dispute over Nijjar's murder, Foreign Minister Melanie Joly says.

Oct. 29, 2023: Tens of thousands of Sikhs turn out in Surrey, British Columbia, at the same gurdwara, a Sikh house of worship, where Nijjar was killed to vote in an unofficial referendum on the creation of an independent Sikh state.

Nov. 21, 2023: India's anti-terror agency files a case against Gurpatwant Singh Pannun, a Sikh separatist, stating that he warned Air India passengers in video messages shared on social media that their lives were in danger.

Nov. 22, 2023: A senior Biden administration official says U.S. authorities thwarted a plot to kill Pannun in the United States and issued a warning to India over concerns the New Delhi government was involved.

Feb. 5, 2024: India's High Commissioner says in an interview with Canada's Globe and Mail newspaper that India will not provide information to Canadian investigators over Nijjar's murder until Canada shares evidence.

April 30, 2024: The White House describes as a serious matter a Washington Post report that an officer in India's intelligence service was directly involved in both Nijjar's killing and the foiled plot to kill Pannun in the U.S.

India's foreign ministry said the report contained "unwarranted and unsubstantiated imputations."

May 3, 2024:Canadian police charge three people linked to Nijjar's murder, a source directly familiar with the matter says.

Aug. 27, 2024 Canadian police warn Gurpatwant Singh Pannun, an aide to Nijjar, of an increased threat to his life, a prominent Sikh separatist says.