TEHRAN - A researcher with dual French-Iranian nationality held for months in a notorious Tehran prison will not be tried on espionage charges, her lawyer said Tuesday. But she and another French researcher still face other security-related charges.

Iranian prosecutors dropped the spying charges against Fariba Adelkhah after an hours-long hearing, Saeid Dehghan told The Associated Press. Both Adelkhah and Roland Marchal will remain in custody on charges of spreading propaganda, their lawyer said.

Iranian officials disclosed in July that Adelkhah, a prominent anthropologist who often traveled to Iran for research on post-revolutionary Iranian society, had been arrested on espionage charges. Her friend and fellow researcher Marchal was arrested as he tried to visit her, France revealed in October. He is being held in a men's ward.

In December, France summoned Iranian envoy to Paris, saying it considered the months-long detention of Adelkhah and Marchal "unacceptable" and sought permission for consular officials to visit them.

Iran does not recognize dual nationality for its citizens.

Also in December, Adelkhah and Kylie Moore-Gilbert, an academic and co-prisoner from Australia, went on hunger strike to protest their detention. The strike was revealed by the Center for Human Rights in Iran. They were confirmed by Sciences Po's research center CERI, where Adelkhah works.

Abdekhah's lawyer did not say if she remained on hunger strike.

Moore-Gilbert, a University of Melbourne scholar on the Middle East, has been jailed since October 2018.

Two Australians were freed from Iran in October while Australia freed an Iranian in what appeared to be a prisoner swap.

Meanwhile, Iran had indicated a willingness to make prisoner exchanges with the United States after freeing a Chinese-American scholar from Princeton held for three years in a prisoner swap.

However, these moves all came prior to the U.S. killing of Iran's top general last week, which has dramatically increased tensions between Washington and Tehran.