Canadian police have arrested three suspects in the 2023 killing of Canadian citizen and Sikh activist Hardeep Singh Nijjar.

The suspects, all Indian nationals, are facing first-degree murder and conspiracy charges.

Assistant police commissioner David Teboul said he could not comment on the nature of the evidence or the motive.

"This matter is very much under active investigation," Teboul said.

The men are reportedly accused of being shooters, drivers and spotters when Nijjar was gunned down in June last year outside a Sikh temple in Surrey, a suburb of Vancouver with a large Sikh population.

Diplomatic row

Canadian Prime Minister Justin Trudeau said last year that his government was investigating "credible allegations" that Indian government agents had been involved in Nijjar's death.

Commissioner Teboul said the probe continues and it "include investigating connections to the government of India." 

India had labeled Nijjar, 45, a "terrorist" over his advocacy for an independent Sikh state. The accusation shocked the Sikh community in Canada, who make up roughly 2% of Canada's population. 

Nijjar was an outspoken advocate for the creation of a separate Sikh state known as Khalistan, a movement that saw violent clashes between supporters and the Indian government in the 1970s and 1980s. The movement is outlawed in India.

Following Nijjar's death, both India and Canada expelled senior diplomats. At the height of the tensions, India temporarily suspended visa services for Canadian citizens.

The rift between the two countries put major Western countries in an uncomfortable position.

US assassination plot

In a separate incident in November last year, prosecutors in the United States charged an Indian national they say was hired to assassinate a Sikh activist Gurpatwant Singh Pannun.

Pannun is general counsel for Sikhs for Justice, which supports the secession of Punjab province from India.

Earlier this week the Washington Post published the name of an official at India's spy agency, the Research and Analysis Wing, the paper said directed the hit. 

India on Tuesday strongly rejected the claims, saying that the report made "unwarranted and unsubstantiated" claims.

lo,rm/nm (Reuters, AFP)