Doha, Qatar – The United States and Iran each released five detainees on Monday in a prisoner swap deal that also gives Tehran access to US$6bn in long-frozen oil funds.

US President Biden thanked Oman, Qatar, Switzerland and South Korea for their role in negotiating the prisoner swap with Iran.

“I give special thanks to the Emir of Qatar, Sheikh Tamim bin Hamad, and to the Sultan of Oman, (His Majesty) Haitham bin Tarik, both of whom helped facilitate this agreement over many months of difficult and principled American diplomacy,” Biden said in a statement.

The five Americans freed by Iran, including a businessman arrested in 2015, landed in Doha just before 5:40pm (1440 GMT) on a Qatari jet, hours after the unblocked funds were credited to Iranian accounts in Qatari banks.

The five were greeted on the tarmac before walking in the setting sun to a terminal building, three of them with their arms round each other’s shoulders.

Two of the Iranian detainees arrived in Qatar, Iranian media said. The other three released by the United States have opted to remain there or in a third country, Tehran said.

The trigger for the exchange was the release of the US$6bn in funds, frozen by US ally South Korea under sanctions against Iran, to the Iranian accounts.

Washington has denied the US$6bn is a ransom payment, insisting the money will be used for humanitarian purposes.