WASHINGTON (AP) — The Biden administration has cleared the way for the release of five American citizens detained in Iran by issuing a blanket waiver for international banks to transfer $6 billion in frozen Iranian money from South Korea to Qatar without fear of U.S. sanctions. In addition, as part of the deal, the administration has agreed to release five Iranian citizens held in the United States.

Secretary of State Antony Blinken signed off on the deal late last week, but Congress was not notified of the decision until Monday, according to the notification, which was obtained by The Associated Press.

The waiver is likely to draw criticism of President Joe Biden from Republicans and others that the deal will boost the Iranian economy at a time when Iran poses a growing threat to U.S. troops and Mideast allies.

The waiver means that European, Middle Eastern and Asian banks will not run afoul of U.S. sanctions in converting the money frozen in South Korea and transferring it to Qatar’s central bank, where it will be held for Iran to use for the purchase of humanitarian goods.

The transfer of the $6 billion was the critical element in the prisoner release deal, which saw four of the five American detainees transferred from Iranian jails into house arrest last month. The fifth detainee had already been under house arrest.

Due to numerous U.S. sanctions on foreign banks that engage in transactions aimed at benefitting Iran, several European countries had balked at participating in the transfer. Blinken’s waiver is aimed at easing their concerns about any risk of U.S. sanctions.