Iran has released four journalists who had been jailed on spying charges.
All of the prisoners held dual US-Iranian citizenship.
In exchange, it is reported that the US has released seven Iranian-Americans.
It comes as International sanctions against Iran look likely to be lifted today, in the latest stage of the country's nuclear deal.
The atomic watchdog, the IAEA, is expected to confirm Iran has scaled back its nuclear activities, which means billions of dollars of assets will be unfrozen.
Iran's Foreign Minister Mohammad Javad Zarif has hailed the end of sanctions as a victory for his country:
