An Indian man accused of plotting to kill a Sikh separatist in New York City has pleaded not guilty in federal court.

Nikhil Gupta appeared for the first time in court on Monday afternoon after being extradited from the Czech Republic and landing in the US on Friday.

He is charged by US authorities with trying to hire a hitman to assassinate Sikh separatist leader Gurpatwant Singh Pannun, a dual US-Canadian citizen.

US prosecutors allege Mr Gupta was directed by an unnamed Indian government official. India denies having anything to do with the alleged plot.

Mr Gupta, 52, walked into the Manhattan federal courtroom shortly after 12:30 EDT (17:30 BST) on Monday wearing a blue sweater and black Nike sweatpants, holding his hands behind his back.

After waiving the reading of his indictment, Mr Gupta was asked by Judge James Cott to enter his plea. “Not guilty,” his lawyer, Jeff Chabrowe, said on his behalf.

Prosecutors asked that Mr Gupta be held in a detention centre until his trial.

Mr Gupta’s lawyer said they would file a bail application at a later date, meaning Mr Gupta will be detained for now.

His lawyer also complained to the judge during the 20-minute arraignment about the conditions of Mr Gupta’s detention. He had not been provided a vegetarian meal since he arrived at a Brooklyn detention facility on Friday, the lawyer said.

“Essentially, my client has not been able to eat,” he said.

He would also need to be allowed to pray, Mr Chabrowe said.

Judge Cott said Mr Chabrowe should speak to him again on Tuesday if those issues had not been resolved.

Speaking to reporters after the hearing, Mr Chabrowe called the case “a complex matter for both India and the US”.

He said people should refrain from “jumping to conclusions” about the allegations against Mr Gupta.

“We will pursue his defence rigorously,” he said.

Mr Gupta’s hearing was also attended by several Khalistan activists, including one who held the movement’s flag outside the courthouse.

Mr Gupta is scheduled to appear in court again on 28 June.

In November, US prosecutors charged Mr Gupta with a plot to kill at least four Sikh separatists in North America, including Mr Pannun. The charges against him carry up to 20 years in prison.

Mr Gupta paid $100,000 (£79,000) in cash to a hitman to assassinate Mr Pannun, prosecutors said. The hitman, they added, was an undercover federal agent.

Mr Pannun is a dual US-Canadian citizen living in New York.

He is the general counsel for Sikhs for Justice, an organisation based in the US that supports the broader Khalistan movement, which calls for an independent homeland for Sikhs, who make up about 2% of India’s population.

Mr Pannun was designated a terrorist by the Indian government in 2020, an allegation he denies.

He was also an associate of Hardeep Singh Nijjar, a Sikh separatist leader who was shot dead in Canada in his car last year.

The murder led to a deterioration in India-Canada ties after Canadian Prime Minister Justin Trudeau alleged there were “credible allegations” that Delhi had been involved. India denied the accusations.

In November, the White House said it had raised the alleged assassination plot against Mr Pannun with India at the most senior level.

Indian officials distanced themselves from the alleged plot, saying such actions were against government policy. Delhi said it had formed a committee to investigate the allegations against Mr Gupta.

A group of US lawmakers urged Secretary of State Antony Blinken to lead a “strong diplomatic response” that would ensure all parties involved “are held accountable”, according to a 17 June letter that was obtained by the BBC.

The US and India “have a crucial relationship across multiple domains”, and their ties must “be grounded in shared commitment to democratic principles and the rule of law”, the letter adds.

In January, India’s Supreme Court rejected a plea from Mr Gupta which asked it to aid his release and help him get a fair trial. The petition in India claimed Mr Gupta was arrested by “self-claimed” US federal agents and had not yet been given a fair trial.

India’s top court said it would not intervene in the case, adding that it was up to the government to take action.