The Italian authorities freed Iranian engineer Abedini Najafabadi Mohammad on Sunday and he flew home to Iran soon after, ANSA news agency reported.
Abedini was arrested on 16 December by the Italian authorities at Milan Malpensa airport under a US warrant and had been held in prison in the city.
The US Justice Department accused Abedini, along with another Iranian citizen, of supplying Iran with drone technology used in the January 2024 attack on a US outpost in Jordan, which killed three American soldiers.
Many political commentators believe a deal may have been struck whereby Italy promised to free Abedini if Iran release the Italian journalist Cecilia Sala from prison, which Tehran did last week.
However, neither the United States, nor Italy, nor Iran have confirmed whether a deal was in fact struck.
Three days after his arrest Cecilia Sala, a freelance journalist with Il Foglio newspaper and Chora Media, was arrested in Tehran on charges of violating the laws of the Islamic Republic. After 21 days of imprisonment in Evin prison, Sala was freed and returned to Italy on Wednesday 8 January.