TEL AVIV — Hamas directly criticized President Joe Biden on Tuesday, saying his comments that the militant group is “backing away” from a cease-fire deal in the Gaza Strip caused “great astonishment and disapproval” and demonstrated “blind bias” toward Israel.

The unusually direct comments cast doubt on the prospects of a near-term agreement, which the Biden administration said last week it hoped to conclude in the coming days. The criticism also came as the Israeli military recovered the bodies of six more hostages from southern Gaza, and as the enclave’s civil defense force said at least 12 people were killed in a strike on a school in Gaza City. Israel accused Hamas militants of using the school as a “command and control center.”

The row between Hamas and Biden comes as U.S. Secretary of State Antony Blinken shuttled between Israel, Egypt and Qatar on Tuesday on a mission to pressure all sides to conclude a deal. The proposal sponsored by the United States includes a six-week cease-fire, the release of scores of Israeli hostages and Palestinian detainees, and the withdrawal of Israeli forces from major population centers in Gaza.

The framework, which the United States says is a compromise that incorporates both Israeli and Hamas interests, was provided to Hamas and Israel last week. On Monday, Blinken emerged from a three-hour meeting with Prime Minister Benjamin Netanyahu saying that the Israeli leader had accepted the framework but that core aspects of implementation still needed to be negotiated.

“Israel accepts the bridging proposal. It’s now incumbent upon Hamas to do the same,” Blinken told reporters in Tel Aviv.

Biden followed those remarks by telling reporters at the Democratic National Convention in Chicago that “Israel says they can work it out,” but “Hamas is now backing away.”

The Hamas statement says that the group agreed to an earlier cease-fire framework that was consistent with both Biden’s remarks on a deal and a U.N. Security Council resolution, but that the deal changed after Israel placed new demands and Washington accepted them.

“Biden and Blinken’s statements are misleading claims and do not reflect the true position of the movement, which is keen to reach a cessation of aggression,” Hamas said. “We reaffirm our commitment to what we agreed upon with the mediators on July 2.”

Although both U.S. mediating partners Qatar and Egypt signed on to the latest “bridging proposal,” they largely view it as an American creation that they will try their best to convince Hamas to accept.

One former Egyptian official familiar with the discussions said the United States no longer appears to be “bridging” anything and was simply adopting “Israel’s demands.”

“I am no longer hopeful about what is happening,” the official, who spoke on the condition of anonymity to discuss the closed-door negotiations, said of the prospects of reaching a deal.

During Blinken’s meeting Tuesday with Abdel Fatah El-Sisi, the Egyptian president said Cairo would not accept the presence of Israeli forces along the Egypt-Gaza border.

While the disconnect between Hamas and the United States raises doubts about a deal, there are also significant discrepancies between U.S. and Israeli negotiators, according to diplomats who, like others in this story, spoke on the condition of anonymity to discuss a sensitive situation.

When Blinken announced that Israel had accepted the proposal, Israeli, Qatari and Egyptian officials privately expressed surprise and confusion. Israel has not yet agreed on how to implement some of the deal’s most critical components, including which Palestinian prisoners will be released, how to vet Palestinians returning to their homes in northern Gaza, and the status of the Israel Defense Forces (IDF), both at the Rafah crossing in the south and along the Israeli-built Netzarim Corridor that carves the territory in two.

Among the most stubborn sticking points for the Israelis is forging an agreement on the removal of Israeli troops from the Philadelphi Corridor that runs the length of Gaza’s border with Egypt. Netanyahu has insisted on a lasting military presence, Hamas demands a full withdrawal, and U.S. negotiators are trying to find a middle ground that allows for a reduced presence of Israeli soldiers until a long-term Arab security force can be stood up, said officials familiar with the negotiations.

Publicly, Netanyahu has not denied that he agreed with the U.S. proposal, but he has also insisted he will never back down on the issue of the Philadelphi Corridor, a narrow buffer zone Israel and Egypt established to prevent weapons smuggling into Gaza from the Sinai Peninsula.

“The prime minister insisted that Israel remain in the Philadelphi Corridor in order to prevent terrorists from rearming,” Netanyahu’s spokesman David Mencer said Tuesday. “We’re conducting these negotiations with a firm eye on the vital security interests of Israel, as opposed to those who advised us just to give in.”

U.S. officials also said Netanyahu’s public comments that Israel will not withdraw from the Philadelphi Corridor were patently unhelpful to the negotiations. “Maximalist statements like this are not constructive to getting a cease-fire deal across the finish line,” said a senior administration official briefing reporters.

In response to the confusion surrounding the U.S. position, Blinken told reporters in Qatar late Tuesday that the United States does not support the long-term occupation of Gaza. He also said that the U.S. proposal includes clear schedules and locations for IDF “withdrawal” from the territory.

But the issue of the Philadelphi Corridor has been so difficult to resolve that some suspect Netanyahu may have raised it to forestall a deal, which is strongly opposed by his right-wing cabinet.

“The Philadelphi Corridor issue isn’t a made-up issue, though the prime minister is making it harder to resolve than it needs to be,” said Aaron David Miller, a Middle East expert who has advised multiple Republican and Democratic administrations. “Stopping smuggling of weapons from Sinai into Gaza is critically important for preventing a Hamas resurgence.”

“For Egypt, it’s a sovereignty issue and an economic one, since the smuggling trade is a lucrative one,” he said. “The IDF is prepared to implement any decision reached by the government, which suggests the issue is Netanyahu’s politics, not Israeli security.”

Retired Maj. Gen. Israel Ziv, who served as the head of the IDF’s operations division, said Israeli negotiators generally have only a “partial mandate” to agree to a humanitarian cease-fire deal that would halt the fighting, allow most Palestinians to return to their homes and secure the release of more than 100 hostages still held in Gaza, dozens of whom the Israeli government has assessed are still alive.

Ziv said that the talks, taking place alongside U.S. and international efforts to prevent a war between Israel, Hezbollah and Iran, have enabled Netanyahu to “kind of launder in the Philadelphi Corridor issue, understanding that the U.S. and the other players see de-escalation as their top interest.”

Netanyahu has shifted the focus of the negotiations toward convincing Egypt to allow Israel to control the border area, in exchange for the potential involvement of the Palestinian Authority as supervisors of the crossing.

“The deal now depends on Egypt and on the U.S. to get Egypt on board,” Ziv said. “Which means there is a high probability that there will be an understanding on the principles of the deal by the weekend, though we may still see, at least, another round of negotiations.”

High-ranking Israeli military figures for months have expressed willingness to show flexibility on security concerns needed to finalize a deal.

Last week, IDF Chief of Staff Herzi Halevi said that along the Philadelphi Corridor, the military was “preparing options for whatever the political echelon decides,” including the withdrawal of troops from the border region.

“If they decide that we remain in Philadelphi, we will do so with a strong presence. If they decide that we will monitor from afar and carry out raids whenever indications arise, we will know how to do that,” Halevi said.

Mahfouz reported from Cairo. Lior Soroka in Tel Aviv contributed to this report.