TEHRAN — Iran announced on Saturday that it had released four Iranian-Americans as part of a prisoner exchange with the United States, a move that came as the United States and Iran were negotiating the final steps before the expected lifting of oil and financial sanctions related to Iran's nuclear program.
The exchange, first reported by Iran and confirmed hours later by Obama administration officials, removed a big source of irritation in the difficult relationship between the two countries, which broke down more than three decades ago during the 1979-1981 Tehran hostage crisis.
Obama administration officials, sensitive to criticism that they have capitulated to Iran on many issues, attributed the break in the prisoner dispute to the new climate of diplomacy they have cultivated with Iran during the nuclear negotiations and after the deal was finalized.
"They understood this was a priority for us, and that we'd never give it up," said a senior administration official, speaking on the condition of anonymity. "We consistently said it was independent from the nuclear negotiations but of great importance to us."
U.S. officials also disclosed for the first time that another American, whom they identified as Matthew Trevithick, had been detained by Iranian authorities in recent months, and that he had been permitted to leave Iran. They described him as a student but shared no further information.
They also said they were still working to free Siamak Namazi, an Iranian-American business consultant who worked for a United Arab Emirates-based oil company and was seized in Tehran in mid-October.
Nearly all of the negotiations took place in Geneva, the Americans said, and arrangements for the departure of those freed in Iran had been done by Switzerland, which attends to U.S. interests in Iran in the absence of diplomatic relations.
The other freed Americans — Amir Hekmati, Jason Rezaian, Saeed Abedini and Nosratollah Khosravi, whose incarceration had not been publicly reported — had not yet left Iran by Saturday evening. Rezaian, a 39-year-old Californian who became the Washington Post's bureau chief in Tehran in 2012, had been languishing in Tehran's Evin Prison since July 2014.
The U.S. officials described the released Iranians as convicts or suspects in sanctions violations — offenses that Iran's government has never recognized as legitimate. They also said that as part of the negotiations, the Americans had rescinded international arrest warrants on 14 other Iranians suspected of sanctions violations.