The United States on Tuesday demanded that Iran free an Iranian-American journalist sentenced to 10 years in prison, in the first known arrest of an American by Tehran since a prisoner swap last year.

Reza Valizadeh, who holds both Iranian and US citizenship and worked for US-funded Persian-language Radio Farda, was convicted of charges of working with a hostile government, according to his lawyer.

“We strongly condemn this sentencing and call for his immediate release and the release of all political prisoners in Iran,” State Department spokesman Matthew Miller told reporters.

“The Iranian government has repeatedly suppressed press freedom through threats, intimidation, detentions, forced confessions and the use of violence against journalists in Iran,” Miller said.

“We remind US citizens of the warning on our website that has existed for years and years — do not travel to Iran due to the risk of kidnapping and the arbitrary arrest and detention of US citizens.”

Iran does not recognize dual nationality.

Valizadeh’s lawyer, Mohammad Hossein Aghasi, told VOA Persian that it was a heavy sentence, as working for US-backed media earlier carried a charge of engaging in propaganda rather than of cooperating with a hostile government.

Iran in September 2023 freed five US citizens as part of a prisoner swap. President Joe Biden’s administration at the time agreed to arrange the release of some $6 billion in Iranian oil revenue that had been frozen by US ally South Korea due to sanctions enforcement.

Biden’s Republican opponents, who return to power next month, lashed out at the deal as offering an economic lifeline to the cleric-run state, but the Biden administration defended it as a necessary means to release all remaining Americans from detention.

The administration, however, later backtracked on releasing the money to Iran after Tehran-backed militants Hamas launched a major attack on Israel on October 7, 2023.

The sentencing comes after major setbacks in the region for Iran, with Israel’s military degrading Lebanese Shiite militia Hezbollah and Islamist fighters overthrowing Syrian leader Bashar al-Assad, Iran’s main Arab ally.