Gupta, 52, is scheduled to be arraigned in a Lower Manhattan court on federal murder charges. The charges against him carry a maximum penalty of 20 years in prison.
He is currently incarcerated at the federal Metropolitan Detention Center in Brooklyn, according to jail records. The BBC has contacted his lawyer for comment.
On Monday, the Czech Attorney General confirmed media reports that Mr. Gupta had been extradited to the United States on Friday, June 14.
Last November, U.S. prosecutors charged Mr. Gupta with plotting to kill at least four Sikh separatists in North America, including Mr. Pannun.
Prosecutors said Mr Gupta paid a hitman $100,000 (£79,000) in cash to assassinate Mr Pannun. The assassin was an undercover federal agent, they added.
Mr. Pannun is a dual U.S.-Canadian citizen living in New York.
He is general counsel for Sikhs for Justice, a U.S.-based organization 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, which he denied.
He was also an associate of Sikh separatist leader Hardeep Singh Nijjar, who was shot dead in his car in Canada last year.
The killing soured India-Canada relations after Canadian Prime Minister Justin Trudeau claimed there were “credible allegations” that Delhi was involved. India has denied these accusations.
Last November, the White House said it had raised charges of an assassination plot against Mr. Pannun with India at the highest level.
Indian officials have distanced themselves from the alleged conspiracy, saying such actions run counter to government policy. Delhi said it had formed a committee to probe the allegations against Mr. Gupta.
A group of US lawmakers urged Secretary of State Antony Blinken to lead a “robust diplomatic response” that ensures all parties involved are held accountable, according to a June 17 letter obtained by the BBC.
The United States and India “have an important relationship across a variety of areas” and their relationship “must be based on a shared commitment to democratic principles and the rule of law,” he added.
In January, India's Supreme Court rejected Gupta's request for release and a fair trial. The extradition petition claimed Mr. Gupta was arrested by “self-styled” US federal agents and has not yet received a fair trial.
India's highest court will not intervene in the case, he said, adding that it is up to the government to take action.
