Canada worked "very closely" with the United States on intelligence that Indian agents had been potentially involved in the murder of a Sikh leader in British Columbia earlier this year, a senior Canadian government source said on Tuesday.

Prime Minister Justin Trudeau announced on Monday that domestic intelligence agencies were actively pursuing credible allegations tying New Delhi's agents to the shooting of Hardeep Singh Nijjar, 45, in June.

"We've been working with the U.S. very closely, including on the public disclosure yesterday," the source said. The evidence in Canada's possession would be shared "in due course", said the official who did not give a name due to the sensitivity of the information. Trudeau on Tuesday told reporters that the case had far-reaching consequences in international law, and urged the Indian government to take the matter seriously and help Canada fully investigate the matter.