An Indian national extradited to the United States from the Czech Republic pleaded not guilty on Monday to involvement in an alleged plot to kill a Sikh separatist leader on US soil.

Nikhil Gupta, 52, who was detained at Prague airport in June 2023 on a US warrant, arrived in the United States on Friday.

Gupta appeared before a federal magistrate judge in New York on Monday and pleaded not guilty to charges of murder-for-hire, according to court filings.

“This extradition makes clear that the Justice Department will not tolerate attempts to silence or harm American citizens,” Attorney General Merrick Garland said in a statement.

“Nikhil Gupta will now face justice in an American courtroom for his involvement in an alleged plot, directed by an employee of the Indian government, to target and assassinate a US citizen for his support of the Sikh separatist movement in India,” Garland added.

The Justice Department unsealed the charges against Gupta in November, accusing him of conspiring with an unidentified Indian government official to kill a US citizen of Indian origin in New York City.

The alleged target of the plot was Gurpatwant Singh Pannun, a US and Canadian citizen who is affiliated with a New York-based group called Sikhs for Justice that advocates for the secession of Punjab, a northern Indian state with a large Sikh population.

According to court documents an Indian government agency employee identified only as “CC-1” recruited Gupta in May 2023 to carry out the assassination of Pannun.

Gupta allegedly contacted an individual he believed to be a criminal associate to hire a hitman. The individual was in fact a confidential source working with the US Drug Enforcement Administration (DEA).

Canada and India had a major diplomatic row last year after Prime Minister Justin Trudeau linked New Delhi to the killing of Canadian citizen Hardeep Singh Nijjar, also a Sikh separatist, in June.

Canadian authorities have arrested four Indian nationals in connection with Nijjar’s murder, which took place in the parking lot of a Sikh temple in Vancouver.

Nijjar — who immigrated to Canada in 1997 and became a citizen in 2015 — had advocated for a separate Sikh state, known as Khalistan, carved out of India.

He had been wanted by Indian authorities for alleged terrorism and conspiracy to commit murder.

‘Hold Modi’s India accountable’

US intelligence agencies have assessed that the plot on American soil was approved by India’s top spy official at the time, Samant Goel, The Washington Post reported in April.

India has denied involvement in the murder plots and pledged to carry out an investigation into the allegations.

“If someone gives us any information, we would definitely look into it,” Indian Prime Minister Narendra Modi told the Financial Times in December.

Pannun welcomed Gupta’s extradition as a “starting point” for the global community to “hold Modi’s India accountable.”

“The attempt on my life on American Soil is the blatant case of India’s transnational terrorism challenging America’s sovereignty and unequivocally proves that Modi’s India believes in using violence to suppress the dissenting political opinion,” Pannun said in a statement.

The Khalistan movement has largely petered out within India, but in the Sikh diaspora — whose largest community is in Canada, with around 770,000 people — it retains support among a vocal minority.