Speaking on the repeated US demands that Iran unconditionally release three American citizens held in jail in Iran for various crimes, Iranian President Hassan Rouhani said he believes the environment for such a release would be much better if the US would release all the Iranians it is holding as well.
The US is currently holding some 19 Iranian citizens, all on charges of having violated the anti-Iran sanctions in some form. US officials have not addressed this question directly, but with the new P5+1 nuclear deal lifting most of those sanctions the time may be right for releases on both sides.
As much sense as a mutual release makes, however, it’s unlikely to happen, as the Obama Administration is still trying to appear like they’re being “tough on Iran” to placate both Israel and Congressional hawks, and angrily demanding the Americans be released without any reciprocation plays better to that end than actually getting them released in a deal.
Two of the three Americans in Iranian prison are there on spying allegations, while the other held on charges of harming national security by attempting to “sway Iranian youth away from Islam.” A fourth American, former FBI agent Robert Levinson, is sometimes listed as being held by Iran, but Iran denies this, and the US has produced no evidence to suggest he is.