The White House acknowledged Saturday that the prisoner exchange with Iran that included Washington Post reporter Jason Razaian was connected to the international nuclear deal with Tehran but that it was also was just a “one-time-only” situation that will not open the door to prisoner swapping between the rival nations.

As Secretary of State John Kerry and Iranian Foreign Minister Mohammad Javad Zarif recently concluded the nuclear talks, they also “recognized a unique opportunity … for release of those citizens,” a senior Obama administration official said on a conference call with reporters.

“This is one-time-only type of arrangement. We don't anticipate replicated in the future, but if the window opened up (we’d) wanted to take advantage of it,” the official also said.

The exchange was four Americans held in Iran for seven Iranians sentenced or awaiting trial in the United States who are not associated with terrorism.

The other Americans released were pastor Saeed Abedini, former U.S. Marine Amir Hekmati and Nosratollah Khosravi.

Administration officials also said the seven Iranians were offered clemency and were not associated with violent crimes.

They also said none of the Americans or Iranians were used a “bargaining chip” in the nuclear deal and that negotiations for their release were only indirectly connected to the nuclear deal, for fear of ruining it.

The United States also removed any Interpol red notices and dismissed any charges against 14 Iranians previously sought but not in U.S. custody.

They were released hours before Kerry announced that Iran had fulfilling its duties toward curtailing its pursuit of a nuclear weapon, in exchange for the lifting of crippling economic sanction and the return of $100 billion in frozen assets.

“This has been an answer to prayer,” said the pastor’s wife, Naghmeh Abedini. “We look forward to Saeed's return and want to thank the millions of people who have stood with us in prayer during this most difficult time.”

It was not yet clear when the Americans could return to the U.S. They were first being flown to Germany, for a medical evaluation at a U.S. facility in that country.

One additional American, student Matthew Trevithick, was freed unrelated to the others' release. Trevithick was already on his way home before the exchange was announced.

The deal came just before International Atomic Energy Agency certified later Saturday that Iran had met all commitments under the landmark nuclear deal with six world powers. The deal ends sanctions against Iran and frees more than $100 billion in the nation’s frozen assets.

“Today marks the first day of a safer world,” Kerry said.

A spokeswoman for House Speaker Paul Ryan, R-Wis., said the congressman and his staff are “glad” about the Americans being released but awaiting details on the “ransom paid for their freedom.”

Rezaian, 39, the Post’s Tehran-based correspondent, 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. Rezaian was initially arrested in July 2014 with his wife and two photojournalists, but the other three were freed shortly afterward.

Kris Coratti, spokeswoman for The Washington Post, said, "while we are hopeful, we have not received any official word of Jason's release."

Hekmati, 32, of Flint, Michigan, was arrested in August 2011, accused of being a spy. His family says he was in Tehran to visit his ailing grandmother and had received permission to make the visit from the Iranian Interests Section of the Pakistani Embassy in Washington D.C. Initially convicted of spying and sentenced to death, the initial verdict was overturned and Hekmati was instead given 10 years.

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 have been going on for the past two months.

Abedini was trying to build a secular orphanage in his homeland when he was arrested in September of 2012. A native of Iran, he had made frequent trips back to the Islamic Republic to see members of his family, even after converting to Christianity. He had previously been in trouble with Iranian authorities for allegedly organizing Christian gatherings in private homes as part of an underground movement.

“We’re delighted this day has finally arrived,” said Jay Sekulow, chief counsel of the American Center for Law & Justice, which has represented Abedini’s Boise, Idaho, family since his arrest. “Pastor Saeed should never been imprisoned in the first place. He spent more than three years in an Iranian prison. We’re grateful for the millions of people who have stood with us in our ongoing efforts.”

The family of Trevithick said he had gone to Iran in September for a four-month, intensive language program at the Dehkhoda Institute, a language center affiliated with Tehran University. They said he runs a humanitarian group called the Syria Research and Evaluation Organization based in Turkey.

“We are profoundly grateful to all those who worked for his release and are happy for all the families whose loved ones are also heading home,” the family said.

The release of prisoners did not include Robert Levinson, a former FBI agent last seen in Iran but whose status is unknown. The 67-year-old disappeared in 2007 while working for the CIA on an unapproved intelligence mission.

The administration official said U.S. negotiators raised the issue of Levinson “at every opportunity” but were not able to achieve resolution on his whereabouts or on bringing him home. However, the officials said such discussions will continue.

Levinson traveled to Kish Island and checked into a hotel, purportedly investigating cigarette smuggling. He met U.S. fugitive Dawud Salahuddin, the last man known to see him.

The CIA family paid Levinson's family more than $2 million and some staffers lost their jobs over his unauthorized work. A proof of life video surfaced in 2011, saying Levinson 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.

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.

FoxNews.com's Greg Wilson and Perry Chiaramonte and the Associated Press contributed to this report