U.S. and Iranian officials say Iran is releasing four detained Iranian-Americans in exchange for seven Iranians held or charged in the United States.
U.S. officials say the four Americans, Washington Post reporter Jason Rezaian, former Marine Amir Hekmati, pastor Saeed Abidini and Nosratollah Khosravi-Roodsari, were to be flown from Iran to Switzerland on a Swiss plane and then brought to a U.S. military base in Landstuhl, Germany, for medical treatment.
A U.S. official confirmed to CBS News that a fifth American, Matthew Trevithick, would also be released from Iranian custody.
In return, the U.S. will either pardon or drop charges against seven Iranians - six of whom are dual citizens - accused or convicted of violating U.S. sanctions. The U.S. will also drop Interpol "red notices" - essentially arrest warrants - on 14 Iranian fugitives it has sought.
Iran also committed to continue cooperating with the U.S. to determine the whereabouts of Robert Levinson, who disappeared in Iran in 2007.
Levinson's family issued a statement to CBS News senior investigative producer Pat Milton about the swap.
"We are happy for the other families. But once again Bob Levinson has been left behind. We are devastated," the statement said.
The announcement of the exchange came as the International Atomic Energy Agency was close to certifying that Iran had met all commitments under the landmark nuclear deal with six world powers. U.S. Secretary of State John Kerry was meeting in Vienna with Iranian Foreign Minister Mohammad Javad Zarif and other officials involved in the accord, and it was expected that such certification could come Saturday.
The release of the prisoners, along with the expected implementation of the nuclear deal and sanctions relief, caps a week of intense U.S.-Iran diplomacy that took an unexpected turn on Tuesday with the detention by Iran of 10 U.S. Navy sailors and their two boats in the Persian Gulf.
They were released in less than 24 hours after Kerry intervened with Zarif in multiple telephone calls that administration officials hailed as a channel of communication opened because of the nuclear negotiations.
Certification by the IAEA would allow Iran to immediately recoup some $100 billion in assets frozen overseas. The benefits of new oil, trade and financial opportunities from suspended sanctions could prove far more valuable for Tehran in the long run.
In a statement, Post publisher Frederick Ryan Jr. said, "We couldn't be happier to hear the news that Jason Rezaian has been released from Evin Prison. Once we receive more details and can confirm Jason has safely left Iran, we will have more to share."
Rezaian's lawyer, Leila Ahsan, told CBS News she had not received any official papers confirming his release.
Hekmati's lawyer, Mahmoud Alizadeh Tabatabaei, said Hekmati called him earlier Saturday from prison.
"He told me that judiciary officials have called for a meeting with him. But I've not been formally informed if he is free now," he said, adding that negotiations for the prisoners' release has been going on for the past two months.
A report by the semi-official ISNA news agency quoted a statement from the Tehran prosecutor's office as saying the inmates were freed "within the framework of exchanging prisoners." It did not elaborate.
Rezaian was born in California and holds both U.S. and Iranian citizenship. He was convicted in closed proceedings last year after being charged with espionage and related allegations. The Post and the U.S. government have denied the accusations, as has Rezaian. Rezaian was the Post's Tehran correspondent and was accredited to work in the country by the Iranian government.
Hekmati, of Flint, Michigan, was detained in August 2011 on espionage charges. Hekmati went to Iran to visit family and spend time with his ailing grandmother.
Abedini of Boise, Idaho, was detained for compromising national security, presumably because of Christian proselytizing, in September 2012. He was sentenced in 2013 to 8 years in prison.
Separately, Levinson disappeared in Iran in 2007 while working for the CIA on an unapproved intelligence mission. American officials are unsure if the former FBI agent is even still alive. Iranian officials deny knowing where he is. Levinson traveled to Kish island and checked into hotel, purportedly investigating cigarette smuggling. He met U.S. fugitive Dawud Salahuddin, the last man known to see him.
The CIA paid Levinson's family over $2 million and some staffers lost their jobs over his unauthorized work. A proof of life video surfaced in 2011, saying he was held by a group. His family received photos that year, too, of Levinson bearded, shackled, wearing orange jumpsuit and holding signs in broken English. He has seven children. He suffers from diabetes and high blood pressure.
The Obama administration has said the Americans came up in every conversation with the Iranians.