Paris - Families and friends of a growing number of Europeans imprisoned in Iran gathered in Paris Saturday to call for their release.

The French government this week denounced the plight of seven French citizens held in Iranian prisons, calling the detentions 'unjustifiable and unacceptable.'

Iran has detained a number of foreigners and dual nationals over the years, accusing them of espionage or other state security offenses. Many were convicted and sentenced after secretive trials in which rights groups said they were denied due process.

Supporters and family members of four of the current French prisoners - Louis Arnaud, Fariba Adelkhah, Benjamin Briere and Cecile Kohler - held a solemn, silent rally for their release Saturday on a plaza overlooking the Seine River.

The supporters said all were wrongly accused and some were in fragile physical or psychological health, or placed in isolation. 'They are deprived of the most basic rights,' unable to contact loved ones, the supporters said in a statement.

Arnaud was arrested September 28 as he was traveling in Iran as a tourist, according to France's Foreign Ministry. Another prisoner, Bernard Phelan, was detained last year and is in need of medical care that is not being provided, according to the ministry.

Earlier Saturday, dozens of people gathered in a park beneath the Eiffel Tower to show support for detained Belgian aid worker Olivier Vandecasteele. Vandecasteele, who worked for many years for aid group Doctors of the World, was arrested in Tehran in February 2022. Doctors of the World said the conditions of his detention were putting Vandecasteele's life at risk.

Most of the European prisoners were detained before the protests that have shaken Iran since September over the death of a young woman, Mahsa Amini, in police custody. Concerns about the detentions have grown as Iranian authorities have cracked down on the protesters.