US authorities thwarted a plot to kill a Sikh separatist in the United States and issued a warning to India over concerns the government in New Delhi was involved, the Financial Times (FT) reported on Wednesday, citing unnamed sources.

There was no immediate response from India’s foreign ministry, or from the US embassy in New Delhi to requests for comment on the report.

The Financial Times said that the sources did not say if the protest to India resulted in the plot being abandoned by the plotters, or if it was foiled by the Federal Bureau of Investigation.

The protest to New Delhi was registered after Indian Prime Minister Narendra Modi was welcomed on a state visit by President Joe Biden in June, the report said.

The report comes two months after Canada said there were “credible” allegations linking Indian agents to the June murder of a Sikh separatist leader, Hardeep Singh Nijjar, in a Vancouver suburb.

India has rejected Canada’s accusations.

Apart from the diplomatic warning to India, US federal prosecutors have also filed a sealed indictment against at least one suspect in a New York district court, the FT report said.

The paper identified Gurpatwant Singh Pannun as the target of the foiled plot.

The FT report said Pannun had declined to say whether US authorities had warned him about the plot, but quoted him as saying he would “let the US government respond to the issue of threats to my life on American soil from the Indian operatives”.

Pannun, like Nijjar, is a proponent of a decades-long, but now fringe demand to carve out an independent Sikh homeland from India named Khalistan.

India’s anti-terror agency recently filed a case against him for threatening not to let flag carrier Air India operate anywhere in the world while warning its passengers of danger to their lives.

The case against Pannun was registered under various provisions of the Unlawful Activities (Prevention) Act 1967 and under sections of the Indian Penal Code, the National Investigation Agency had said in a statement on Monday.

“Pannun threatened that Air India would not be allowed to operate in the world … in his video messages, released on Nov 4,” it had said, adding that he had urged Sikhs not to travel on Air India flights from Sunday, “claiming a threat to their lives”.

Canada worked very closely with the United States on intelligence that Indian agents were potentially involved in Nijjar’s murder, a senior Canadian government source told Reuters in September.

The FT report mentioned that the US shared details of the thwarted plot with a wider group of allies after Canada’s public accusation.