An Indian citizen accused of attempting to kill a Sikh separatist in New York pleaded not guilty in federal court in Manhattan on Monday.The defendant, Nikhil Gupta, has been charged with murder for hire linked to a foiled plot to assassinate Gurpatwant Singh Pannun, a dual U.S. and Canadian citizen who advocates for an independent Sikh state. Gupta, 52, is being held at the Metropolitan Detention Center in Brooklyn, a federal administrative detention facility.Gupta’s lawyers have said he is a law-abiding businessman unjustly caught up in the escalating geopolitical “crossfire” between the United States and the Indian government.“This is a complex matter for both our countries,” said Jeffrey Chabrowe, Gupta’s criminal defense lawyer in the United States. “It is extremely important that we refrain from rushing to conclusions so early in the process. Background and details will develop that may cast government allegations into an entirely new light. We will pursue his defense vigorously and ensure he receives full due process, regardless of outside pressures.”Gupta, who had been detained in the Czech Republic since last June, arrived in New York on Friday, according to people familiar with the matter who spoke on the condition of anonymity to discuss sensitive legal proceedings.Federal prosecutors say a senior Indian government employee ordered the assassination of Pannun in May and hired Gupta to arrange the hit. The Washington Post in April identified the employee, who was an officer in India’s spy agency, as Vikram Yadav. U.S. authorities broke up the plot last June before it could be carried out. Pannun works as general counsel for the New York-based Sikhs for Justice, a group that seeks to carve from India an independent Sikh state called Khalistan.Gupta’s attorney in India, Rohini Musa, wrote in a petition to the Indian Supreme Court that her client is being unfairly prosecuted, saying there is “nothing on record to link the Petitioner to the massive alleged plot to assassinate the alleged victim.”Musa complained that Gupta received adverse legal advice from a Czech government-appointed attorney “under the undue influence of … U.S. Agencies” during the initial phase of his detention. She said India and the United States were “going back and forth to blame each other for their foreign policy.”Prosecutors said that hours after the assassination of Sikh separatist Hardeep Singh Nijjar in Canada on June 18, 2023, the unnamed Indian government agent sent Gupta a “video clip that showed Nijjar’s bloody body slumped in his vehicle.” Hours later, according to the indictment, the Indian government agent sent Gupta the street address of Pannun. The same person messaged Gupta two days later, saying that the assassination of Pannun was a “priority now.”In September, Canadian Prime Minister Justin Trudeau said there were “credible allegations” that agents of the Indian government were behind Nijjar’s killing.Gupta’s extradition coincides with a visit by U.S. national security adviser Jake Sullivan to New Delhi. Sullivan, who arrived in India on Monday, met with his counterpart, Ajit Doval, and External Affairs Minister S. Jaishankar. The United States is seeking to deepen its strategic partnership with India in large part to build a counterweight to China’s growing ambitions in the region.On Monday, Sen. Jeff Merkley (D-Ore.) sent a letter to Secretary of State Antony Blinken stating that the relationship must be based on more than mutual strategic interests and grounded in respect for rule of law. He urged the administration to press the Indian government “to hold those involved criminally responsible.”Co-signed by four other senators — three Democrats and one independent — the letter stated that now that India’s general election has concluded, with the Bharatiya Janata Party and Prime Minister Narendra Modi returning to power, the United States has an opportunity to include the issue as a “core agenda item” with New Delhi.“The United States must be firm and resolute in opposing transnational repression, no matter the perpetrator,” the letter stated.Aaron Schaffer contributed to this report.