Iran emerged from years of economic isolation when world powers lifted restrictions in return for Tehran curbing its nuclear ambitions.
The International Atomic Energy Agency (IAEA) in Vienna confirmed that the conditions set after major talks last July had been fulfilled, paving the way for Iran to resume oil exports.
Within minutes, the United States formally lifted banking, steel, shipping and other sanctions.
In a dramatic move, the Islamic Republic of Iran announced the release of five American prisoners including Washington Post journalist, Jason Rezaian, as part of a prisoner swap with the US. In return, US President Barack Obama also pardoned three Iranian-Americans charged for violating sanctions against Iran.