Iran’s foreign ministry reportedly said on Thursday that banks in South Korea are taking steps to release Teheran’s frozen assets.

According to China’s state Xinhua news agency on Thursday, the Iranian foreign ministry said in a statement that the U.S. has provided guarantees that it will fulfill its obligation to release the funds, which it said were illegally frozen under sanctions for years.

The ministry also posted on Twitter that the procedure has begun to release billions of dollars of Iranian assets that it says was illegally frozen by the U.S. for a few years.

Earlier, Iran reportedly moved five U.S. nationals from prison to house arrest on Thursday in the first step of an emerging deal with Washington that would unfreeze Tehran's assets in South Korea and free several jailed Iranians.

In the rare deal, Iran reportedly agreed to release the prisoners if the funds were unfrozen.

Iran has about seven billion U.S. dollars at the Industrial Bank of Korea and Woori Bank, which include a South Korean payment for oil imports from Iran, that have been frozen since 2018 due to U.S sanctions on Iranian funds.