Tehran has accused Washington of "hostage taking" after an Iranian political scientist was arrested in the United States and accused of being an agent of Iran's government.
Foreign Ministry spokesman Saeed Khatibzadeh made the accusation on January 20, a day after U.S. authorities announced the arrest of Kaveh Afrasiabi, an Iranian citizen with U.S. permanent residency.
The Justice Department said Afrasiabi was arrested at his home in Watertown, Massachusetts, on January 18 on charges of "acting and conspiring to act as an unregistered agent" of Tehran.
If convicted on both charges, Afrasiabi faces a maximum sentence of 10 years in prison.
"For over a decade, Kaveh Afrasiabi pitched himself to Congress, journalists, and the American public as a neutral and objective expert on Iran," John Demers, assistant attorney general for national security, said in a statement on January 19.
Demers said that Afrasiabi "was actually a secret employee of the government of Iran and the Permanent Mission of the Islamic Republic of Iran to the United Nations...who was being paid to spread their propaganda."
Khatibzadeh dismissed the accusations against Afrasiabi as baseless and referred to him as a "well-known university lecturer."
The spokesman expressed hope the new U.S. administration, which took over on January 20 following the inauguration of President Joe Biden, would "distance itself" from President Donald Trump's "hostage-taking approach."
News of Afrasiabi's arrest followed reports that Iranian authorities had convicted an Iranian-American businessman on spying charges.
Iranian media reports identified the convict as Emad Sharqi and described him as the deputy head for international affairs at an Iranian venture-capital company called Sarava.
Washington and Tehran have exchanged several prisoners in recent years, during which Iran authorities have jailed several Americans on alleged spying charges dismissed by the United States as baseless.