Iran’s former reformist president Mohammad Khatami has called for the release of all political prisoners, notably opposition chiefs Mir Hossein Mousavi and Mehdi Karroubi, a newspaper reported on Thursday.
Last week, the authorities freed around 15 reformists, journalists and lawyers, notably prominent rights lawyer Nasrin Sotoudeh.
They have also announced pardons for 80 others rounded up in connection with anti-government protests claiming massive fraud in the 2009 re-election of president Mahmoud Ahmadinejad.
Dozens of others are still behind bars, though legal authorities have not said how many.
Both men were candidates in the 2009 presidential election and spearheaded the protests its outcome.
On Wednesday, Intelligence Minister Mahmoud Alavi said more prisoners would be released within a month, without giving a number.
Newly elected President Hassan Rouhani, who has the backing of reformists and moderates in the Islamic republic, has pledged to work for political and cultural liberalisation.