The transfer of funds will “trigger a carefully choreographed sequence that will see as many as five detained U.S. dual nationals leave Iran and a similar number of Iranian prisoners held in the U.S. fly home,” the news agency reported on Sunday, citing eight Iranian and other sources familiar with the negotiations.

As a gesture of goodwill, Tehran on August 10 moved four American citizens detained in Iran from prison to house arrest. They joined a fifth prisoner, who was already under house arrest.

US Secretary of State Antony Blinken said at the time the move was the first step in a process that would lead to their return home.

An informed source told Reuters that Doha has hosted at least eight rounds of indirect talks between the two sides in separate hotels.

Doha will also implement a financial arrangement under which it will pay banking fees and make sure the unfrozen funds are not spent on items subject to US sanctions, three of the sources said, adding that the prisoner exchange will also happen in Qatar.

“Iran will purchase food and medicine and Qatar will pay directly,” a senior diplomat said.

The funds had been frozen in South Korea after the administration of former US president Donald Trump unilaterally withdrew from the 2015 Iran nuclear deal in May 2018.