In this July 10, 2019 photo, the Iranian flag waves outside of the UN building that hosts the International Atomic Energy Agency, IAEA, office inside in Vienna, Austria. (PHOTO / AP)

TEHRAN – A senior Iranian official said on Friday the exchange of prisoners between Iran and the United States will take place "simultaneously" with the release of Iran's frozen assets in banks of the Republic of Korea (ROK).

"The US prisoners in Iran will leave simultaneously with the irreversible release of our illegally held citizens and the full transfer of illegally held assets in South Korea, similar to the recently freed assets in Iraq," Mohammad Jamshidi, Iranian President Ebrahim Raisi's deputy chief of staff for political affairs, said in a post on X, previously known as Twitter.

READ MORE: Iran says jailed citizens in US, frozen assets in ROK to be released

The prisoner swap and unfreezing of assets were announced Thursday night in a statement by the Iranian Foreign Ministry.

US Secretary of State Antony Blinken said there would be no sanctions relief for Iran in exchange for the release of the Americans

The ministry said that the country's funds "had been illegally frozen in the ROK's banks for a few years by the United States”, adding: "Iran has obtained the necessary guarantees from the US for its continued commitment to obligations in this regard."

It is estimated that Iran has funds worth over $7 billion in ROK's two banks, which refuse to process them for fear of possible US penalties.

US National Security Council spokesperson Adrienne Watson said in a statement on Thursday that Washington had received confirmation about the release of the "unjustly detained Americans," whose number she put at five, in Iran.

In remarks at a press conference on the same day, US Secretary of State Antony Blinken said that there would be no sanctions relief for Iran in exchange for the release of the Americans.

Iranian authorities say the Americans were arrested and jailed on spying charges.

ALSO READ: Over 3,000 US troops arrive in Mideast amid tensions with Iran

Over the past months, Iran has repeatedly expressed its readiness to swap prisoners with the US as a humanitarian issue under the precondition that the latter acts "realistically”.