Republican presidential candidates seized on the Hamas attacks on Israel Saturday to criticize President Biden, whom they sought to cast as enabling the offensive by Palestinian militants.

Several of the primary contenders argued that there was a connection between the surprise assault and a recent hostage release deal between the Biden administration and Iran, a longtime backer of Hamas.

Former President Donald J. Trump, who has frequently presented himself as a unflinching ally of Israel and who moved the U.S. embassy from Tel Aviv to Jerusalem in 2018, blamed Mr. Biden for the conflict.

“Sadly, American taxpayer dollars helped fund these attacks, which many reports are saying came from the Biden Administration,” Mr. Trump said in a statement. “We brought so much peace to the Middle East through the Abraham Accords, only to see Biden whittle it away at a far more rapid pace than anyone thought possible.”

In exchange for the release of five Americans held in Tehran, the Biden administration agreed in August to free up $6 billion in frozen Iranian oil revenue funds for humanitarian purposes. The administration has emphasized that the money could be used only for “food, medicine, medical equipment that would not have a dual military use.”

Mr. Trump, the G.O.P. front-runner, was not alone in assailing Mr. Biden, as the entire Republican field weighed in on the attacks on Saturday.

In a video posted on X, formerly known as Twitter, Gov. Ron DeSantis of Florida faulted the Biden administration for its foreign policy decisions in the Middle East.

“Iran has helped fund this war against Israel, and Joe Biden’s policies that have gone easy on Iran has helped to fill their coffers,” he said. “Israel is now paying the price for those policies.”

A spokesman for the Biden campaign directed questions about Saturday’s attacks to the National Security Council, which disputed G.O.P. candidates’ claims that there was a connection between the release of the funds and the attacks.

“Not a single cent from these funds has been spent, and when it is spent, it can only be spent on things like food and medicine for the Iranian people,” Adrienne Watson, a spokesperson for the National Security Council, said in a statement. “These funds have absolutely nothing to do with the horrific attacks today, and this is not the time to spread disinformation.”

In a statement issued through the White House, Mr. Biden pledged solidarity with Israel and said that he had spoken with Benjamin Netanyahu, the country’s prime minister.

“The United States unequivocally condemns this appalling assault against Israel by Hamas terrorists from Gaza, and I made clear to Prime Minister Netanyahu that we stand ready to offer all appropriate means of support to the Government and people of Israel,” Mr. Biden said. “Terrorism is never justified. Israel has a right to defend itself and its people.”

Republicans have repeatedly sought to burnish their pro-Israel bona fides during recent election cycles. In April, Mr. DeSantis visited Jerusalem to show his support for Israel, while former Gov. Asa Hutchinson of Arkansas wore lapel pins featuring the U.S. and Israeli flags during the first primary debate in August.

Yet while the G.O.P. candidates rallied around the longtime U.S. ally on Saturday, there is a growing divide in the party between foreign policy hawks and those who favor a more isolationist approach.

In addition to criticizing Mr. Biden on Saturday, former Vice President Mike Pence had harsh words for fellow Republicans who prefer a more hands-off approach to conflicts abroad.

“This is what happens when @POTUS projects weakness on the world stage, kowtows to the mullahs in Iran with a $6 Billion ransom, and leaders in the Republican Party signal American retreat as Leader of the Free World,” Mr. Pence wrote on X. “Weakness arouses evil.”

Other Republican candidates, including Nikki Haley, who was an ambassador to the United Nations under Mr. Trump, and Senator Tim Scott of South Carolina, denounced the attacks as acts of terrorism.

“Make no mistake: Hamas is a bloodthirsty terrorist organization backed by Iran and determined to kill as many innocent lives as possible,” Ms. Haley said in a statement.

Mr. Scott also joined some of his rivals in taking on Mr. Biden: “The truth is though, Joe Biden funded these attacks on Israel,” he wrote in a post on X. “America’s weakness is blood in the water for bad actors, but this is worse than that. We didn’t just invite this aggression, we paid for it.”

Former Gov. Chris Christie of New Jersey echoed the criticism of his Republican rivals in a social media post, calling the release of $6 billion by the Biden administration to Iran “idiotic.” Gov. Doug Burgum of North Dakota and Mr. Hutchinson similarly sought to connect the attack with the release of humanitarian funds for Iran.

Vivek Ramaswamy, the biotech entrepreneur, called the attacks “barbaric and medieval” in a post on X.

“Shooting civilians and kidnapping children are war crimes,” he wrote. “Israel’s right to exist & defend itself should never be doubted and Iran-backed Hamas & Hezbollah cannot be allowed to prevail.”