Five Americans detained in Iran have been placed under house arrest as the first step in a planned prisoner exchange between Tehran and Washington.

The deal will also see the release of about $6 billion in Iranian government assets frozen after U.S. sanctions, according to a lawyer for one of the detainees.

According to current U.S. sanctions against Iran, if the proposed agreement is approved, Iran will only be permitted to use the money to purchase food, medicine, or other humanitarian needs. According to the agreement, the funds will be managed by Qatar’s national bank.

When former U.S. President Barack Obama announced a similar deal in 2015, Republican lawmakers slammed him fiercely.

Sources said several jailed Americans were transferred on Thursday from their cells in Tehran’s notorious Evin prison to a facility in the capital, where they will be placed under house arrest until the prisoner exchange occurs, according to The New York Times.

Before Thursday, the lawyer said one of the Americans was already under house arrest. Before their relocation abroad, previously released foreign prisoners, including Americans, have been placed under house arrest.

Siamak Namazi, Emad Shargi, and Morad Tahbaz are the three Americans held in Iran who the American authorities have recognised. According to two sources familiar with the situation, two more Americans are detained in Iran, but their families have chosen not to name them publicly.

Unknown numbers of green card holders, or permanent residents of the United States, are being held in custody, including Shahab Dalili, who has been there since 2016. It appears that only Americans are involved in the prisoner exchange.

The prisoner swap agreement also prompted the release of almost $6 billion that U.S. sanctions had frozen in South Korean banks in addition to the exchange of inmates held by both nations.

From 2012 through 2019, Washington permitted South Korea and other nations to purchase Iranian oil, but Tehran was denied access to the earnings. Iran could only use the money to make authorised purchases for humanitarian purposes.

The Iranian regime has long sought the release of American prisoners held in Iran in exchange for access to the funds.

As part of the deal, an unidentified number of Iranians held in the United States will be transferred from U.S. custody to Iranian custody. The exact time frame for this step remains unknown.