Three of the four Americans released by Iran as part of a prisoner swap deal have arrived in Germany after a brief stop in Switzerland on January 17.
The three Americans are Jason Rezaian, the Washington Post's Tehran bureau chief, Saeed Abedini, a pastor from Idaho, and Amir Hekmati, a former Marine from Flint, Michigan.
The fourth Iranian-American released, Nosratollah Khosravi-Roodsari, has not yet left Tehran, senior U.S. officials said.
Speaking on condition of anonymity, officials said that Khosravi-Roodsari decided not to board the plane that left for Switzerland.
Senior U.S. diplomat Brett McGurk tweeted a photo of himself welcoming Rezaian as he arrived at the airport in Geneva.
"Overwhelmed to greet Jason #Rezaian, his wife, Yegi, mother, Mary + Saeed #Abedini + Amir #Hekmati to #Geneva after safely departing #Iran," McGurk wrote in another subsequent tweet.
"We are relieved that this 545-day nightmare for Jason and his family is finally over," said Fred Ryan, The Washington Post's publisher, in a statement.
A fifth prisoner, the American student Matthew Trevithick, has been released separately.
Iran announced the release of the five Americans on January 16 on the same day as international sanctions on Tehran were lifted.
"When Americans are freed, that's something we can all celebrate," U.S. President Barack Obama said in a televised statement from the White House on January 17.
Rezaian had been imprisoned in Iran for more than a year on espionage charges. He and The Washington Post have repeatedly denied the charges, saying he was arrested as a bargaining chip in a larger political game.
Christian pastor Abedini, an Iranian-American had been in jail for three years after being convicted of undermining national security.
Former U.S. Marine Hekmati had been serving 10 years after being found guilty of cooperating with hostile governments.
Under the prisoner swap deal, the United States on January 16 offered clemency to seven Iranians, six of whom are dual U.S.-Iranian citizens, who had been convicted or are awaiting trial in the United States.
Western media have named the Iranians as Nader Modanlo, Bahram Mechanic, Khosrow Afghahi, Arash Ghahreman, Tooraj Faridi, Nima Golestaneh, and Ali Saboonchi.
The deal also saw Washington dismiss charges against 14 other Iranians.
The Swiss Foreign Ministry said the prisoner swap took place after 14 months of confidential discussions in Switzerland.
There are a dozen Iranians imprisoned or facing legal proceedings in the United States on sanctions-busting charges, according to a recent Reuters review of cases. U.S. Prosecutors say they violated economic sanctions against Iran by supplying technology that could have been used to bolster its military and nuclear programs.
The lifting of sanctions came as the UN's nuclear watchdog agency announced that Tehran had fulfilled its obligations to restrict its nuclear programs under a landmark deal agreed with world powers last year.