Iran's judiciary confirmed Tuesday the arrest of French-Iranian academic Fariba Adelkhah, after the French foreign ministry said she had been detained and denied contact with consular staff.
"She is among suspects that have been recently arrested," judiciary spokesman Gholamhossein Esmaili said, without specifying the accusations against her.
"Now is not an appropriate time to give more information on this case," Esmaili told reporters at a news conference broadcast by the jucidiary's news website Mizan Online.
The detention of Adelkhah, a well-known expert on Iran and Shiite Islam at France's prestigious Sciences Po university, risks increasing tension between Paris and Tehran at a critical moment in efforts to save a landmark 2015 nuclear deal.
On Monday French President Emmanuel Macron called on Tehran to explain why Adelkhah had been arrested, expressing concern for her welfare.
"What has happened worries me a great deal," Macron told reporters during a visit to Belgrade. "We have been aware of this for some days.
"I have expressed my disagreement and asked President (Hassan) Rouhani for clarification," he said, adding that France had so far received no meaningful explanation.
The French foreign ministry confirmed Adelkhah's dual nationality on Monday and said she had been denied contact with consular staff.
Asked about French requests for access, Iran's judiciary spokesman said a decision about how to respond would be taken at "an appropriate time".
Adelkhah, 60, is the latest Iranian national with a Western passport to be arrested in Iran.
British-Iranian Nazanin Zaghari-Ratcliffe, a project manager with the Thomson Reuters Foundation, has been jailed in Tehran since 2016 on sedition charges, a detention that has caused major tensions with Britain.