Biden says only Hamas stands in way of cease-fire, but questions about Israel remain

Since President Joe Biden's extraordinary move to lift the veil of secrecy surrounding sensitive negotiations aimed at ending the conflict in Gaza -- by detailing the terms of the deal on the table -- U.S. officials have launched into a flurry of diplomatic activity to maximize pressure on Hamas to accept the deal and to ensure Israel would stand by it.

Despite the hard sell from the administration and Biden's appeal to all sides, the many open questions about the long-term provisions of the proposal may jeopardize its future.

On Monday, Biden spoke by phone with the Emir of Qatar -- another critical mediator in the negotiations -- in order to confirm "Israel's readiness to move forward with the terms that have now been offered to Hamas," according to the White House.

During their conversation, Biden affirmed that "Hamas is now the only obstacle to a complete ceasefire and relief for the people of Gaza," a readout of the call said.

The president's latest engagement builds on calls Secretary of State Antony Blinken held over the weekend with half a dozen foreign ministers of Middle Eastern countries that regularly communicate with Hamas leaders and can exert considerable sway over the group.

Hamas leaders issued a statement reacting positively to Biden's address covering the proposal on Friday but have yet to issue any response on the proposal itself, which was transmitted to the group days ago.

While the State Department has urged Hamas to take the deal outright, spokesperson Matthew Miller also suggested on Monday that there was still room for compromise.

"We think this is a serious enough proposal that Hamas should just accept it, but if there need to be further negotiations, we think those all imminently bridgeable -- if, and this is the if -- if Hamas wants a deal," he said.

But across Washington, officials were peppered with questions about Israel's willingness to lay down arms in exchange for the release of scores of hostages held inside Gaza.

White House national security spokesman John Kirby denied that Biden's decision to convey information about the proposed deal was a play to ensure Israeli Prime Minister Netanyahu would abide by the country's commitments.

"This wasn't about jamming the prime minister or the war cabinet," Kirby said. "This was about laying bare for the public to see how well and how faithfully and how assertively the Israelis came up with a new proposal, how it shows how much they really want to get this done."

Netanyahu's conviction was called into question when his office reaffirmed Israel's commitment to ensuring the "destruction of Hamas's military and governing capabilities, the freeing of all hostages and ensuring that Gaza no longer poses a threat to Israel" before the war ends.

"Under the proposal, Israel will continue to insist these conditions are met before a permanent ceasefire is put in place," an Israeli statement reads. "The notion that Israel will agree to a permanent ceasefire before these conditions are fulfilled is a non-starter."

U.S. officials and the president himself have admitted that the proposed deal contains significant gray areas, particularly in the second and third phases of the agreement which call for "a permanent end to hostilities" and "the major reconstruction of Gaza" without imposing strict timetables.

Analysts say the ambiguity is intentional and that the framework designed to allow both sides to interpret the terms as favorable enough to implement the agreement and gradually ease tension.

However, Hamas has spurned any offer that doesn't ensure the group's longtime survival inside Gaza -- and Netanyahu's comments are unlikely to persuade the militants that this proposal is any different.

Brian Katulis, a senior fellow on U.S. foreign policy at the Middle East Institute, argues that this latest chapter of negotiations reflects a change in approach rather than substance.

"The goal appears to be to spotlight stonewalling by Hamas and right-wing members of the current Israeli government as key roadblocks to a diplomatic settlement," Katulis told ABC News.

Whether the strategy ultimately succeeds, he says, will depend on the Biden administration's ability to apply significant, consistent pressure to both sides.

"For this Biden plan to work will require the U.S. to double down on diplomatic and political efforts in the Middle East, even more so than it already has in the past few months," Kautilis said. "it is not enough to make one-time public statements and expect results."

ABC News' Fritz Farrow contributed to this report.