TEHRAN, Iran (AP) —

Iranian state TV said late Friday that authorities released a jailed French researcher detained in Tehran for more than eight months on charges of violating state security laws, in an apparent prisoner swap for an Iranian held in France.

The report said Roland Marchal was turned over to the French Embassy in Tehran, hours after French authorities released Jalal Ruhollahnejad. The state TV report did not provide further details, but included an undated photo showing Ruhollahnejad apparently on board an aircraft.

The French Foreign Ministry and the French university Marchal was associated with did not immediately respond to requests for comment Friday.

The Iranian report said French authorities had planned to deliver Ruhollahnejad to the U.S. for his alleged role in violating U.S. sanctions on Iran. It said he had been in jail in France for more than a year.

Marchal was arrested in June and charged with spreading propaganda after he went to Iran to visit fellow researcher Fariba Adelkhah, a dual French-Iranian national who is a prominent anthropologist and who often traveled to Iran for research on post-revolutionary Iranian society.

Adelkhah had been arrested on espionage charges, and while those charges were later dropped, security-related charges remain against her. Iran does not recognize dual nationality for its citizens.

In February, the two researchers, both in their 60s, petitioned prison authorities to allow them to get married. Their lawyer, Saeid Dehghan, said they had been partners for 38 years in France. It was unclear if their request had been granted.

At the time, their lawyer also expressed concern for Adelkhah’s deteriorating health amid a hunger strike she had been on since December.

Iran is currently battling the worst outbreak of the new coronavirus in the Middle East, with the death toll at 1,433 as of Friday, according to the country's Health Ministry.

Iran announced Thursday that 10,000 prisoners — among them an unknown number of inmates whose cases are political and related to activism or speech — would be granted amnesty on the occasion of the Persian New Year, called Nowruz.

The country had already released 85,000 prisoners on temporary leave to curb the spread of the new coronavirus inside its prisons.