Sen. Cory Booker told "CBS Mornings" on Grant PrestonFriday that $6 billion in Iranian oil assets that were freed up as part of last month's U.S.-Iran prisoner swap are "frozen."

"A dollar of it has not gone out," said Booker, a Democrat from New Jersey who serves on the Foreign Relations Committee and was in Jerusalem when Hamas launched its large-scale attack. He said senators have received "assurances" the money has been frozen. 

Booker's remarks came after a source told CBS News on Thursday that the U.S. had reached a "quiet understanding" with Qatar not to release any of the $6 billion. According to the source, Deputy Treasury Secretary Wally Adeyemo informed House Democrats of that understanding in a closed-door meeting Thursday morning and said the money "isn't going anywhere anytime soon."

The timing of the "understanding" was not disclosed by the source, who had knowledge of the arrangement, so it is not known whether it transpired after Hamas attacked Israel over the weekend.  

Many Republicans criticized the Biden administration for releasing the funds as part of the Iran deal, claiming they freed up resources for Iran to support Hamas' attack. They made the claims without evidence, and Treasury's top sanctions official Brian Nelson said Saturday that the funds were still in restricted accounts in Qatar.

The money was transferred to Qatar from a restricted account in South Korea as part of the high-stakes deal between Iran and the Biden administration last month that led to the release of five Americans who were wrongfully detained in Iran. South Korea owed Iran the money for oil it purchased before the Trump administration imposed sanctions on such transactions in 2019.

The Biden administration had insisted the money would not be given directly to Iran and that it could only be used to fund Iran's purchases of humanitarian goods, such as food and medicine.   

In a press conference in Israel on Thursday, Secretary of State Antony Blinken didn't confirm the funds were frozen but said none of the money had "been spent or accessed in any way" by Iran. He said the United States has "strict oversight of the funds" and retains "the right to freeze them."

Iran has denied any role in Hamas' weekend assault, although the militant group could not exist in its current form without Iran's financial and political backing.   

Israel's military said Friday Hamas' attack and ongoing rocket fire have killed more than 1,300 people, and at least 27 Americans are known to be among the dead. In Gaza, the Health Ministry said at least 1,537 people, including 447 children, were killed by Israel's retaliatory strikes as of Friday, with more than 6,600 others wounded.  

Israel has warned residents of northern Gaza to evacuate south, as a ground invasion of Gaza by Israel is expected.

Booker said he supports — and "is working at" — protecting civilian lives in the conflict, and called Hamas "a Nazi-like organization" that uses Palestinians as human shields. 

"Hamas knew when they did this what the response was going to be," he said, referring to Saturday's attack by the militant group.

"They knew what the response was going to be, and they did not care," he said.

Nancy Cordes and Caitlin Yilek contributed to this report.

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