(WASHINGTON) — The grisly discovery of six murdered hostages in a tunnel under Gaza over the weekend has sent U.S. officials scrambling to devise a new strategy to advance the already beleaguered negotiations aimed at securing a cease-fire deal and allow dozens of detainees to return home.

“Our team is still working to try to get this to closure,” White House spokesperson John Kirby said Tuesday. “Not that we didn’t have a sense of urgency before — we certainly did, but the killings over the weekend, the executions is the only way to put it, just underscores how important it is to keep that work alive and keep going.”

The Biden administration is now crafting a new framework for a hostage release and cease-fire agreement with its partners Qatar and Egypt and expects to present a finalized, all-encompassing proposal to Israel and Hamas in the coming days, according to a U.S. official.

But Kirby refuted reports that it would be presented to both sides as a “take it or leave it” option and declined to say what would happen if both Israel and Hamas didn’t accept the forthcoming proposal.

“I’m not using that phrase,” he said. “I am simply going to refuse to speculate about what might happen or what might not happen.”

On Monday, the Israeli Ministry of Health said that after examining the bodies of the six recovered hostages, it determined they were shot at close range and killed shortly before they were recovered.

In a statement, a spokesperson for Hamas’ armed wing blamed Israeli Prime Minister Benjamin Netanyahu for the deaths, saying his “insistence on freeing the prisoners through military pressure instead of concluding a deal will mean their return to their families in coffins, and their families will have to choose between dead or alive.”

Sources told ABC News that although the Israel Defense Forces was not conducting a rescue operation at the time the hostages are thought to have been killed, specialized units were operating under Rafah, Gaza’s southernmost city, nearby where the hostages were being held.

“I think when you see an order like that, it shows just what a depraved group we are dealing with in Hamas, when they make clear that they will execute innocent human beings rather than let them be rescued,” State Department spokesperson Matthew Miller said.

Two U.S. officials familiar with ongoing cease-fire talks said representatives from Hamas did not warn mediators that it would begin executing detainees to thwart Israel’s attempts to recover them by any means other than negotiating their release.

However, a Hamas spokesperson said Monday that guards had been operating under instructions to kill hostages in their custody if Israeli forces neared their locations since June, when the IDF successfully freed four hostages in a raid that killed dozens of Palestinians.

High stakes, little leverage

Despite stuttering progress, the Biden administration argues that negotiations were picking up steam in recent days.

“We did have constructive talks last week in the region to try and reach agreement on the final gaps,” Miller said Tuesday. “We made progress on dealing with the obstacles that remain, but ultimately, finalizing an agreement will require both sides to show flexibility.”

But despite immense pressure from the Israeli public, Netanyahu indicated on Monday that he would not back down from his demand that the IDF must maintain a presence in the strategic Philadelphi corridor between southern Gaza and Egypt — a major sticking point in the talks.

Kirby hit back at the prime minister, saying his insistence ran counter to agreements the Israeli government had already made.

“I’m not going to get into a debate with the prime minister,” Kirby said, asserting that multiple draft agreements agreed to by Israel over the last several months called for the removal of the IDF from all densely populated areas of Gaza, including the Philadelphi corridor.  

“That’s the proposal that Israel had agreed to and again,” he said.

Pressure builds on Biden after Israeli strike kills dozens of civilians in Rafah

While the United States has considerable diplomatic sway over Israel, it has much less leverage over Hamas. Through the negotiations, the administration has had little insight into the thinking of its leader, Yahya Sinwar, whom Secretary of State Antony Blinken describes as “the primary decider” in cease-fire negotiations.

Experts see Hamas’ apparent brutalist shift and the execution of hostages near the Philadelphi corridor as a play to push IDF troops away from the area, which could allow the group to rearm. Israel has not indicated that it will continue to pursue rescue missions or alter any operations along Gaza’s southern border.

The prospect of a broader conflict in the Middle East could also hinge on progress in the negotiations between Israel and Hamas. Iran has blamed Israel for carrying out an attack in Tehran that killed Hamas’ political leader, Ismail Haniyeh, in late July and vowed to retaliate. Israel took responsibility for a strike in July that killed Hezbollah commander Fouad Shukr, but has not said if it was also behind the attack that killed Haniyeh in Tehran.

It’s not clear why Iran has not yet carried out its threat, but U.S. officials believe Tehran may be wary of thwarting Gaza cease-fire negotiations.

The hostages still in Gaza

Even before the killing of the six hostages, U.S. and Israeli officials had already assessed that a deal might free a relatively small number of detainees — assessing that fewer than 50 were still living. Officials say there are now 97 hostages remaining in Gaza.

Even before the discovery of the slain hostages, U.S. officials told ABC News that only around a dozen hostages might initially be freed if Israel and Hamas agreed to the framework that was partially outlined by President Joe Biden in May. At least three of the detainees who were discovered dead in the tunnel — including dual American Israeli citizen Hersh Goldberg-Polin, 23 — would have been among them, they say.

Twelve American citizens were taken during Hamas’ Oct. 7 attacks. Two were released in late October, and two more were freed in November as part of a cease-fire deal.

Of the eight Americans who remain detained in Gaza, four have been declared dead. U.S. and Israeli officials believe that four others — Edan Alexander, 19; Sagui Dekel-Chen, 36; Omer Neutra, 22, and Keith Siegel, 65 — could be alive.

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