US Secretary of State Antony Blinken looks on during a meeting with Turkish Foreign Minister Hakan Fidan on the sidelines of the 78th United Nations General Assembly in New York
US Secretary of State Antony Blinken looks on during a meeting with Turkish Foreign Minister Hakan Fidan on the sidelines of the 78th United Nations General Assembly in New York AFP

US Secretary of State Antony Blinken called on India Friday to cooperate with Canada and ensure "accountability" over the killing of a Sikh separatist, after Ottawa accused New Delhi of involvement.

Blinken said the United States has been in touch both with India, with which it has warming ties, and Canada, a close ally which expelled an Indian diplomat earlier this week.

"We want to see accountability. And it's important that the investigation run its course and lead to that result," Blinken told reporters in New York, where he was taking part in the UN General Assembly.

"We would hope that our Indian friends would cooperate with that investigation as well," Blinken said.

Blinken, without commenting directly on the substance of the allegations, said that the United States took "very, very seriously" incidents of "transnational repression."

"I think it's important, more broadly, for the international system that any country that might consider engaging in such acts not do so," he said.

Canadian Prime Minister Justin Trudeau said Monday that Indian agents played a role in the June murder of Hardeep Singh Nijjar, a Canadian citizen, near Vancouver.

Trudeau on Thursday called on India to cooperate on the investigation.

Nijjar was wanted by India for alleged terrorism and conspiracy to commit murder. He was part of the Khalistan movement, which advocates a separate Sikh homeland and was crushed by Indian security forces in the 1980s.

India has come back swinging at Canada, reducing its diplomatic staff and stopping visa services.