Senate Republicans are turning up the heat on the Biden administration’s $6 billion Iran deal in exchange for American prisoners, which they say may have helped fund Hamas’ surprise attack on Israel that has killed at least 700 people and injured 2,000 others.

The deal, which was reached last month, allowed the transfer of Iran's frozen assets held in a South Korean bank to accounts in Qatar. The administration said the money can only be used for humanitarian purposes and the U.S. will have oversight as to how and when the funds are used. There is no evidence that any of that $6 billion has left the Qatari account.

However, Hamas spokesperson Ghazi Hamad told the BBC that they had Iran’s support for the attacks, which began Saturday. A Wall Street Journal report Sunday said Hamas and Hezbollah helped Iran plan the attack.

"If the funds have not been released to Iran, President Biden should immediately void the agreement and freeze the $6 billion ransom payment," Sen. Marsha Blackburn, R-Tenn., posted to X, formerly known as Twitter, on Sunday.

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Israeli airstrike in Gaza City

Fire and smoke rise after an Israeli airstrike in Gaza City, Oct. 7, 2023. (AP Photo/Fatima Shbair)

Thousands of rockets were launched into southern Israel from the Gaza Strip as Hamas terrorists announced "Operation Al-Aqsa Storm" and called on Palestinians from Jerusalem to Israel to attack Israelis.

"There can be no tolerance for calls of de-escalation. Israel is at war and I pray that its forces destroy every last terrorist thug responsible for these atrocities," Sen. Rick Scott, R-Fla., posted to X on Sunday. "The United States will stand strongly with Israel as it defends its citizens and homeland."

Progressive "Squad" members Reps. Alexandria Ocasio-Cortez, D-N.Y., and Ilhan Omar, D-Minn. — vocal critics of Israel — called for a cease-fire between Israel and Hamas on Saturday and condemned the attacks.

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Hamas seize tank

Hamas' armed wing, the Izz ad-Din al-Qassam Brigades, hold a Palestinian flag on an Israeli tank in Gaza City on Oct. 7, 2023. (Getty Images)

Sen. Marco Rubio, R-Fla., shot back at the group on X, saying, "Hamas exists for one reason alone, to wipe out the Jewish state of Israel.

"So Israel has only one option in response to yesterday’s barbaric attack, the permanent elimination of Hamas," he continued. "Anyone demanding Israel not ‘escalate’ or calling for a ‘cease-fire’ is either out of touch with this unfortunate reality or sympathizes with Hamas."

Israel formally declared war on Hamas after the attack. Biden affirmed Israel’s right to defend itself as the Pentagon catapulted assistance to Israel Defense Forces over the weekend.

Sen. Bill Hagerty, R-Tenn., who sits on the Senate Committee on Foreign Relations, posted to X Saturday: "Iran’s leaders call for ‘death to Israel’ & ‘death to America.’ Money is FUNGIBLE. 2+ yrs of lax sanctions enforcement & waivers enabled Iran to bankroll terrorist proxies who seek to murder Israeli civilians & U.S. personnel. Today we saw the results."

Sen. Ted Cruz, R-Texas, said on X that the U.S. must continue to support Israel's "absolute right to self-defense."

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President Biden Delivers Remarks on Israel

President Biden speaks on the terrorist attacks in Israel alongside Secretary of State Antony Blinken at the White House on Oct. 7, 2023. (Samuel Corum/Getty Images)

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Sen. Joni Ernst, R-Iowa, also chimed in and wrote on X: "Make no mistake: Hamas is funded and supported by Iran. America must never appease this ruthless regime and its terror proxies who seek to kill our allies and friends."

Fox News' Adam Shaw and Gabriele Regalbuto contributed to this report.