The Iranian foreign ministry has claimed that no restrictions will be imposed on frozen assets released to Tehran following a politically charged agreement with the Biden administration which will see five imprisoned American citizens return home in exchange for the Iranian regime gaining access to billions of dollars.

"The process of releasing billions of dollars from the assets of the Islamic Republic of Iran, which were illegally seized in South Korea by the United States for several years, has begun," Iran's foreign ministry said in a statement. "The decision on how to utilize these unfrozen resources and financial assets lies with the Islamic Republic of Iran."

That assertion is at odds with comments by John Kirby, a spokesman for the National Security Council, who told CBS News on Thursday that Iran is "only going to be able to use that money for humanitarian purposes."

"We're not changing the rules. We are simply moving the account to a country which will have a system that Iran will be able to access the funds — their funds — for the same purposes that they were able to access those funds under the Trump administration," Kirby said. "The money is only earmarked for humanitarian purposes. The same oversight is going to be applied in this account as was applied in previous accounts."

The Iranian foreign ministry's statement also said that the deal is dependent on a commitment by Washington to release Iranians imprisoned in the U.S. and noted that "prisoners sought by the United States still remain in Iran."

Iran's deputy foreign minister Ali Bagheri Kani insisted on Thursday in a social media post that the U.S. will release several Iranian prisoners as part of the exchange. 

Kirby said that negotiations are ongoing to bring the five Americans home.

"We're only at the first step here getting them out of prison. So I want to be careful how much we talk about this, but I think there's been some misunderstanding here. This is not a matter of ransom, not sanctions relief. There's no U.S. taxpayer dollars involved," Kirby said.

A source familiar with the deal told CBS News that for this first step, Iran is not receiving anything.    

"We have very good reason to demand that if we're going to agree to a process of Americans coming home, we're not going to have our people sitting in Evin Prison over that period," the source said.

The U.S. prisoners involved in the agreement include Siamak Namazi, who has been held in Iran for nearly eight years; Emad Shargi, a Washington, D.C., resident; and Morad Tahbaz, a U.S.-U.K. national.

The other two Americans involved wish to remain unidentified, the White House and State Department said.

A source familiar with the deal told CBS News that it will be considered complete once the Americans return to U.S. soil, which could be as soon as September, though the source acknowledged the diplomacy is highly sensitive and dependent on Iran following through with its end of the process.

Under the terms of the arrangement, some $6 billion of frozen Iranian assets will be transferred to a bank account in a third country over the coming weeks, and Iran will then gain access to it.

Officials in two Western-allied countries told CBS News that Qatar will be the country to hold those funds in restricted accounts.

The U.S. is not lifting any sanctions or giving any U.S. taxpayer money to Tehran, the source familiar insisted. The source said any transfers of funds would be carefully overseen by the U.S. Treasury Department to make sure they comply with existing sanctions and that the restricted funds are used for trade purposes that are permitted.

In:
• Biden Administration
• Tehran
• Sanctions
• Iran
• Joe Biden
• White House

Margaret Brennan

Margaret Brennan is moderator of CBS News' "Face The Nation" and CBS News' senior foreign affairs correspondent based in Washington, D.C.