Canadian police have accused the Indian government of working with a criminal network run by one of India’s most notorious gangsters, Lawrence Bishnoi, to carry out targeted killings of dissidents in Canada.

A diplomatic row broke out between India and Canada on Monday after Canadian police accused Indian diplomats of “criminal” activities in the country, including extortion, intimidation, coercion and harassment, and involvement in targeted killings of Canadian citizens.

Canadian police said they had uncovered evidence that implicated India’s top diplomat, Sanjay Verma, in the killing of Hardeep Singh Nijjar, a Sikh activist who was gunned down outside a gurdwara in a suburb of Vancouver in June last year.

India rejected the allegations as “ludicrous” and claimed they were part of a political agenda by the Canadian prime minister, Justin Trudeau. As tensions between the two countries hit new lows, the two countries expelled each other’s top diplomats.