The transfer of Iran's funds from South Korea to Qatar as part of a US hostage release deal is likely to take 30 to 45 days, American sources told CNN.

According to CNN sources, Iran’s $6 billion, earned from oil sales before the US reimposed sanctions on Iran in 2018, would go through Switzerland before getting to Qatar.

The funds, in a restricted account in South Korea, will be put in restricted accounts in Qatar, from where they will be readily available for “non-sanctionable trade” of goods like food and medicine.

Haaretz said the path of transferring this money is complex and convoluted, and required separate negotiations that took place with the participation of Oman, Britain and Switzerland, in addition to Qatar. It added that the six billion dollars have already moved from South Korea to a Swiss bank, deposited into a special account.

The US Treasury will be heavily involved, as the transfer of funds is expected to take weeks to complete particularly because the US is not lifting any sanctions in order to facilitate the transfer, CNN sources said. Haaretz, however, said the US Treasury is now searching for an option to expedite the process.

White House spokesperson John Kirby said that “there will be a rigorous process of due diligence and standards applied with input from the US Treasury Department."

However, it is not clear how the US will control the disbursements of the funds, which will be kept in six Iranian bank accounts in Qatar in euros, as any transfer of funds will be outside US control of dollar-denominated transactions.

Earlier, Iran's foreign ministry and government media insisted that the unfrozen funds would be under Tehran's direct and unrestricted control.

Five American citizens, already transferred from Tehran Evin prison to a hotel, will be allowed to leave Iran once the funds are unfrozen.