A United Nations human rights group has called on Iran to immediately release two Iranian-Americans, Siamak Namazi and his 81-year-old father Baguer Namazi, describing their imprisonment as a violation of international law.
The two are serving 10-year prison sentences on spying charges.
The call came in an 11-page opinion by the United Nations Working Group on Arbitrary Detention that has not been officially published.
But Namazi’s lawyer, Jared Genser, released the opinion on September 18 as Iranian President Hassan Rohani arrived in New York to attend the UN General Assembly in an attempt to pressure him.
Siamak Namazi, a Dubai-based businessman who advocated better ties between Iran and the United States, has been in Iranian custody since October 2015.
Baquer Namazi, a retired UNICEF official, was detained in February after traveling to Iran to seek his son's release.
They lost an appeal last month of their convictions for “collaboration with a hostile government,” namely the United States.
In their report, the UNWorking Group on Arbitrary Detention dismissed the cases against the Namazis, saying it is part of "an emerging pattern involving the arbitrary deprivation of liberty of dual nationals."
"There is no evidence either Mr. S. Namazi or Mr. B. Namazi had a criminal record, including in relation to national security offenses," the report said.
"There is nothing to indicate that they have ever acted against the national interests of the Islamic Republic of Iran."
"This decision explains in detail precisely why the detention of the Namazis is illegal and in violation of international law," Genser said in a statement.
"It is time for Iran to resolve these cases and allow the Namazis to be reunited with their family,” he added.
Iranian officials have not publicly commented on the report.
Iran does not recognize dual nationality.
The Namazis are among a number of dual nationals held in Iran in what is believed to be a power struggle between the moderates and hard-liners who oppose any opening of the country following the 2015 nuclear deal with the international community on restricting Iran's nuclear program in exchange for relief from economic sanctions.