CNN  — 

An explosive allegation from Canada that the Indian government may have been behind the assassination of a Sikh separatist activist on Canadian soil has triggered a huge diplomatic row and sent relations between the two plummeting.

It all started on Monday, when Canadian Prime Minister Justin Trudeau claimed he has credible information linking India to the killing of prominent Sikh leader Hardeep Singh Nijjar.

Canada’s allegation outraged India, which has vehemently denied the claim, calling it “absurd and motivated.”

Both Canada and India acted swiftly to expel senior diplomats in reciprocal moves earlier this week. And on Thursday, India’s foreign ministry responded by temporarily suspending visa serv