Washington has hit out at the French government over the release of an Iranian, in what appears to be a prisoner swap.
In a harshly worded statement, the US State Department said it “deeply regrets” France’s release of Jalal Rohollahnejad.
It also accused France of failing to uphold its treaty obligations over Mr Rohollahnejad, who is wanted by the US on charges of breaching American sanctions on Iran.
He appears to have been released in exchange for French academic Roland Marchal, who was detained in Iran for more than nine months on claims that he had breached security laws.
"There are outstanding US charges against [Rohollahnejad] related to the illegal export of equipment with military applications in violation of US sanctions," department spokeswoman Morgan Ortagus said.
"The United States and France have a shared interest in bringing those accused of serious crimes to justice, particularly in cases with national security implications.
"It is regrettable in this instance that France failed to uphold its treaty obligations and prevented justice from being pursued."
The two men were released within hours of one another, Iranian state media reported.
France had planned to deliver Mr Ruhollahnejad, an engineer, to the US for his alleged role in breaching American sanctions, Iranian reports said.
He had been in jail in France for more than a year.
Mr Marchal was arrested in Iran in June and had been sentenced to five years in prison.
A senior researcher at France's Sciences Po university, he was detained at the same time as colleague Fariba Adelkhah, who remains in prison.
Mr Marchal was visiting Ms Adelkhah at the time, said Said Dehghan, a lawyer representing both academics.
Ms Adelkhah went on a hunger strike for six weeks from late December.
French President Emmanuel Macron had urged Iranian authorities to also release Ms Adelkhah, a French-Iranian dual citizen.
With the coronavirus outbreak plaguing Iran, Tehran has been forced to make concessions for some of the dual nationals and political prisoners in its custody.
Authorities have granted a medical furlough to US Navy veteran Michael White, who has been imprisoned for more than a year.
British-Iranian Nazanin Zaghari-Ratcliffe, imprisoned since 2016, was temporarily released and allowed to live at her parents' home in the Iranian capital until April 4.
In a speech on Friday to mark Nowruz, the Iranian New Year, supreme leader Ayatollah Ali Khamenei said he would pardon 10,000 convicts, including political prisoners.