Iran has temporarily released more than 54,000 prisoners in an effort to combat the spread of the new coronavirus disease in crowded jails.
Judiciary spokesman Gholamhossein Esmaili told reporters that the inmates were granted furlough after testing negative for Covid-19 and posting bail.
"Security prisoners" sentenced to more than five years will not be let out.
The jailed British-Iranian charity worker Nazanin Zaghari-Ratcliffe may be freed soon, according to a British MP.
Tulip Siddiq cited the Iranian ambassador to the UK as saying that Ms Zaghari-Ratcliffe "may be released on furlough today or tomorrow".
(2/2) If this furlough happens, the British government have an obligation to make it permanent, and not let her be used as a bargaining chip in the weeks to come. I remain concerned that Nazanin has told her family that she has still not been tested for coronavirus. #FreeNazanin
— Tulip Siddiq (@TulipSiddiq) March 3, 2020
End of Twitter post by @TulipSiddiq
Her husband said on Saturday that he believed she had contracted Covid-19 and that the prison authorities were refusing to test her.
But Mr Esmaili insisted on Monday that Ms Zaghari-Ratcliffe had subsequently been in contact with her family and "told them about her good health".