By Bozorgmehr Sharafedin and Lesley Wroughton
Three Iranian-Americans have left Tehran under a prisoner swap following the lifting of sanctions on Iran that is likely to thaw ties further with the United States as Tehran emerges from years of international isolation.
A US official said the Swiss plane had left on Sunday carrying Jason Rezaian, the Washington Post's Tehran bureau chief, Saeed Abedini, a pastor from Idaho and Amir Hekmati, a former Marine from Flint, Michigan, as well as some family members.
One more Iranian-American released under the same swap, Nosratollah Khosravi-Roodsari, was not aboard the aircraft.
A fifth prisoner, the American student Matthew Trevithick, was released separately from the other four on Saturday, a US official said.
"We can confirm that our detained US citizens have been released and that those who wished to depart Iran have left," a senior US administration official said.
Several Iranian-Americans held in US prisons after being charged or convicted for sanctions violations have also been released, their lawyers told the news agency Reuters on Sunday (local time).
The prisoner deal was the culmination of months of diplomatic contacts, secret talks and legal manoeuvring which came close to falling apart because of a threat by Washington in December to impose fresh sanctions on Iran for recent ballistic missile tests.
Speaking to parliament earlier on Sunday, Iranian President Hassan Rouhani hailed the nuclear deal with world powers and the resulting lifting on Saturday of US, European and United Nations sanctions as a "golden page" in Iran's history.
Rouhani, a pragmatist elected in 2013 on promises to end Iran's years of sanctions and isolation, said he looked forward to an economic future less dependent on oil exports.
These are nevertheless likely to jump now that the United States, European Union and UN have scrapped the crippling sanctions in return for Tehran complying with the deal to curb its nuclear ambitions.
But Rouhani noted bitter opposition to the lifting of economic curbs from arch foe Israel, some members of the US Congress and what he called "warmongers" in the region - an apparent reference to some of Iran's Gulf Arab adversaries.
Presenting the draft budget for the next Iranian fiscal year, which begins in March, Rouhani told parliament the deal was a "turning point" for the economy of Iran, a major oil producer which has been virtually shut out of international markets for the past five years.
"The nuclear negotiations which succeeded by the guidance of the Supreme Leader and support of our nation, were truly a golden page in Iran's history," he said.
"The nuclear deal is an opportunity that we should use to develop the country, improve the welfare of the nation, and create stability and security in the region," Rouhani said.
Together, the lifting of sanctions and the prisoner deal help to ease the hostility between Tehran and Washington that has shaped the Middle East since Iran's 1979 Islamic Revolution.
Tens of billions of dollars' worth of Iranian assets will now be unfrozen and global companies that have been barred from doing business there will be able to exploit a market hungry for everything from cars to aeroplane parts.