U.S. authorities announced murder-for-hire charges Wednesday against a man from India who they say plotted to pay an assassin $100,000 to kill a prominent Sikh separatist leader living in New York City after the man advocated for the establishment of a sovereign state for Sikhs.

U.S. Attorney Damian Williams announced the charges against Nikhil Gupta, 52, an Indian national who had lived in India, as an indictment was unsealed in Manhattan federal court.

"As alleged, the defendant conspired from India to assassinate, right here in New York City, a U.S. citizen of Indian origin who has publicly advocated for the establishment of a sovereign state for Sikhs, an ethnoreligious minority group in India," he said in a release.

According to the release, Czech authorities arrested and detained Gupta on June 30 in Czechoslovakia through a bilateral extradition treaty between the U.S. and the Czech Republic. It was not immediately clear when he might be brought to the United States.

India had set up a high-level inquiry after U.S. authorities raised concerns with New Delhi that its government may have had knowledge of a plot to kill a Sikh separatist leader on American soil.

U.S. officials became aware of the plot to kill Gurpatwant Singh Pannun, who is considered a terrorist by the Indian government.

Anne Milgram, administrator of the Drug Enforcement Administration, said in the release that the DEA stopped the plot when a foreign government employee recruited an international narcotics trafficker to commit murder in the U.S.

According to the indictment, the plot was directed by an Indian government agency employee who has described himself as a "senior field officer" with responsibilities in "security management" and "intelligence" and also claims to have served in India's Central Reserve Police Force and been trained in "battle craft" and "weapons." The government employee was identified in the indictment only as "CC-1." Pannun was only identified in court papers as the "Victim."

The Indian government employee recruited Gupta last May to orchestrate the assassination, the indictment said.

It said Gupta contacted an individual he believed to be a criminal associate to help find a hitman to carry out the killing, but the individual actually was a confidential source working with the DEA. The confidential source then introduced Gupta to a purported hitman, but the individual was actually a DEA agent, the indictment said.

India had set up a high-level inquiry after U.S. authorities raised concerns with New Delhi that its government may have had knowledge of a plot to kill a Sikh separatist leader on American soil, an Indian official said on Wednesday.

The U.S. side shared some information and India "takes such inputs seriously since they impinge on our national security interests as well, and relevant departments were already examining the issue," a statement by External Affairs Ministry spokesman Arindam Bagchi said.

In September, Canadian Prime Minister Justin Trudeau said there were credible allegations that the Indian government may have had links to the assassination in that country of Sikh activist Hardeep Singh Nijjar. India rejected the accusation as absurd, but Canada expelled a top Indian diplomat and India responded with the same measure.

Pannun, who is considered a terrorist by the Indian government, has been a leading organizer of the so-called Khalistan referendum, inviting Sikhs worldwide to vote on whether India's Punjab state should become an independent nation based on religion. Organizers of the nonbinding referendum hope to present the results to the U.N. General Assembly in about two years.

Pannun, general counsel with Sikhs for Justice, has been listed as a terrorist by the Indian government. The organization was banned by India in 2019.

Bagchi said that the Indian government formed a high-level inquiry committee on Nov. 18 to look into all the aspects of the matter.