Oman has successfully negotiated the release of an Iranian woman who was detained in the United States for trying to export military equipment to Iran.
An Oman foreign ministry spokesman said Shahrazad Mir Gholikhan had been freed on humanitarian grounds.
"This humanitarian initiative will serve the interests of both countries and stability in the region," the spokesman added.
Gholikhan, 35, was met by her family at Muscat airport in Oman. She said she was looking forward to starting a new life.
Gholikhan was sentenced to five years in December 2008 for attempting to export military equipment to Iran.
She was initially arrested in Vienna, more than four years before being convicted, when US and Austrian agents staged a joint operation and thwarted a plot to export 3,000 Generation 3 night-vision goggles to Ira, in violation of a US embargo against Tehran.
It is not the first time Oman stepped in to mediate between the US and Iran. In 2011, it received two US hikers who were arrested in July 2009 and spent two years in jail in Iran for spying and illegal entry.
A third US hiker who was also arrested was released in September 2010 after Oman paid his bail.