The Washington Post confirmed its journalist Jason Rezaian was among those who "safely left the country" alongside American pastor Saeed Abedini
A plane carrying three American citizens who were imprisoned in Iran has landed in Geneva, Switzerland.
The released inmates departed Iran earlier today as part of a prisoner swap which has also seen the release of several Iranians from US jails.
A US government jet was standing by to greet the trio who were among four US inmates freed as part of the exchange on Saturday.
The fourth man, Nosratollah Khosravi-Roodsari, about whom little is known, is not among them, a US official said.
Those "who wished to depart Iran have left," the Obama administration official, who spoke on condition of anonymity, said.
The Washington Post confirmed its journalist Jason Rezaian was among those who "safely left the country" alongside American pastor Saeed Abedini.
Former US Marine Amir Hekmati who was facing a death sentence in Iran as an alleged spy, was also on board, his family said.
"Today, our brother, son and friend Amir Hekmati has been released from Iran. We have now been officially told that he is on a plane leaving the country," the family said in a statement.
"It is hard to put into words what our family feels right now. But we remain in hopeful anticipation until Amir is in our arms."
A fifth American, student Matthew Trevithnick, who was also freed on Saturday is also understood to have left the country. US officials say his release was not part of the prisoner swap.
From Geneva the three former detainees and two family members were scheduled to travel to a US military base in Germany, the Swiss Foreign Ministry has said.
In exchange for the four American citizens, the US has granted clemency to seven Iranians being held in jails across the United States or awaiting trial.
Several were released from prison on Sunday, their lawyers confirmed.
Six of the Iranians who were in US custody had been accused or convicted of violating economic sanctions.
The prisoner swap was welcomed by US President Barack Obama who told reporters: "Americans unjustly detained are finally coming home".
"When Americans are freed, that's something we can all celebrate," he said in a televised statement from the White House.
It was one of several landmark agreements reached between Western powers and Iran this weekend.
Western powers lifted crippling economic sanctions against Iran on Saturday after it was confirmed Tehran had fulfilled the terms of last year's landmark nuclear deal.
The UN's nuclear watchdog, the International Atomic Energy Agency, said Iran had scaled back its nuclear programme. Western powers had feared Iran had been trying to develop atomic weapons.
Iran's President Hassan Rouhani has heralded the fulfillment of the deal as a "new chapter" for Iran. Iranians have "reached out to the world in a sign of friendliness, and leaving behind the enmities, suspicions and plots, have opened a new chapter in the relations of Iran with the world," he said.
The US has, however, maintained sanctions relating to human rights and terrorism and has now imposed fresh sanctions on Iranian companies and individuals over Iran's ballistic missile programme.