Multiple news agencies say U.S. Secretary of State Antony Blinken has signed off on a sanctions waiver to allow some $6 billion in frozen Iranian assets to be transferred from South Korea to Qatar as part of a U.S.-Iran prisoner swap, with AP saying Congress was notified of the move on September 11.
Tehran had indicated earlier on September 11 that it believed a swap would be finalized soon.
Last month, Iranian and U.S. officials said they had reached an agreement on moving five Americans, all of whom are U.S.-Iranian dual citizens, into house arrest from the notorious Evin prison where they were being held. Only three of the five -- Siamak Namazi, Emad Sharghi, and Morad Tahbaz -- were identified.
The limited custody of the Americans was said to be part of a larger deal involving up to $7 billion in assets frozen in South Korea.
The United States had declined to confirm the amount of money involved and said it was not U.S. taxpayer dollars and denied it was a ransom.
Senior Iranian officials said last month that the five imprisoned individuals would remain in Iran until all conditions -- which reportedly included the release of several Iranian prisoners in the United States -- were met. The identities of the Iranians have not been disclosed.
Iran's Foreign Ministry said through a spokesman on September 11 that $6 billion in assets in South Korea would be unblocked within days and that a swap would take place "in the near future." But the spokesman, Naser Qanaani, said the events were not linked.
Later the same day, AP reported that Blinken signed the blanket waiver for international banks to unfreeze the Iranian assets in South Korea last week and cited a notification to Congress.
It said that as part of the deal, the Biden administration had agreed to release five Iranian citizens held in the United States.
U.S. President Joe Biden has already faced tough criticism from Republicans and others who oppose any deal that might throw a lifeline to an Iranian economy buffeted by U.S. sanctions, with Tehran continuing what they say is disruptive and dangerous behavior in the region.
Mike Turner, the Republican head of the Intelligence Committee in the House of Representatives, has said Congress should consider a travel ban to prevent Americans from traveling to Iran.
The Biden administration has repeatedly emphasized its efforts to end the suffering of unjustly detained individuals and the pain their families suffer during their detention.
Iranian security forces have taken some 40 foreign nationals into custody during a current wave of unrest, often without revealing any charges.
Western countries have repeatedly said that Iran is trying to take advantage of foreign countries by taking dual and foreign nationals hostage to use in prisoner swaps.