The Biden administration’s Gaza ceasefire hopes may be fading in the wake of a top Hamas leader being assassinated deep inside Iran, defense experts told the Daily Caller News Foundations.

The administration and several international negotiators have spent months trying to broker a deal between Israel and Hamas for a ceasefire and the release of the hostages in Gaza, with officials suggesting in recent weeks that remaining “gaps” could be soon narrowed to reach an agreement. But the assassination of Ismail Haniyeh, a key negotiator in the deal, will likely complicate ceasefire talks and erase months of progress, experts told the DCNF. (RELATED: ‘They Want More Time’: Israel Could Be Walking Into A War It Might Not Be Totally Ready For, Experts Say)

Israel has not taken credit for the killing, but Iran and Hamas were quick to assign blame regardless, and some reports indicate that the Israeli forces were secretly behind the operation. His assassination underscores the unique position Israel has found itself in over the last several months — working tirelessly to defeat the terrorist group while trying to negotiate with them at the same time, experts told the DCNF.

“The implication here is that the ceasefire talks and hostage talks are set back a while, to the extent that anyone believed that they were going to happen at all,” Gabriel Noronha, executive director at Polaris National Security and former State Department official, told the DCNF. “From Hamas’ side, internally, they’re not going to feel like doing anything with Israel anytime soon.”

“Talking while fighting is hard under the best of circumstances… it’s a weird thing to do at all, although you have to do it. [The U.S. has] done it, of course, but when you kill the actual negotiator, it’s going to be very hard to find somebody who wants to play that role in the future, because you are now both a diplomat and a target,” Justin Logan, director of defense and foreign policy at the Cato Institute, told the DCNF. “It would be remarkable to me if anybody told you they didn’t think this was a setback for diplomacy.”

Haniyeh joined Hamas in 1997 and led the terrorist group’s political wing since 2017, according to The Washington Post. He was sanctioned by the U.S. and wanted by the International Criminal Court (ICC).

In the ongoing war in Gaza, Haniyeh represented Hamas during ceasefire negotiators with Qatari and Egyptian meditators. Though his death is not unwelcomed by the West, it threatens to complicate ongoing negotiations with Hamas.

Biden officials are now scrambling to keep the deal alive, according to several reports. The strike against Haniyeh in Iran caught the Biden administration by surprise, U.S. officials told The Wall Street Journal.

“This is something we were not aware of or involved in,” U.S. Secretary of State Antony Blinken said in an interview during a trip to Singapore , adding that he did not know “what this [meant]” for ongoing ceasefire discussions. The State Department referred the DCNF to deputy spokesman Vedant Patel’s comments during a press briefing on Wednesday, in which he echoed Blinken’s comments that he didn’t want “to speculate on any potential impacts.” (RELATED: Blinken Reportedly Warns China About Harris’ Stern Views On Relations As Winds Shift Away From Biden)

President Joe Biden held a “tough” phone call with Israeli Prime Minister Benjamin Netanyahu on Thursday to express his frustration that Israel would choose to kill Haniyeh at such a pivotal time for the ceasefire talks, even though his death as a general matter would not be upsetting to the U.S., two U.S. officials told Axios. The phone call was reportedly emotional as Biden “raised his voice” at Netanyahu toward the conclusion of the discussion, insisting that he wanted a ceasefire deal reached within “a week to two weeks,” an Israeli official with direct knowledge of the discussions told Axios.

The Biden administration and the Israeli government have seemingly been at odds for months on how to achieve a ceasefire. Biden put forward a ceasefire proposal in May that he claimed was penned by the Israelis, but Netanyahu seemed to reject the proposal shortly after it was announced.

“I think it’s clear that they have not been synced up on the ceasefire approach at all,” Logan told the DCNF. “Part of it is wishful thinking on the part of the Biden people that, you know, ‘we believe Netanyahu should want this, therefore he probably does want it’ — and they’re not listening to what Netanyahu is saying in reality. I think there has to be some frustration there and a feeling that the world’s only superpower has little leverage to control this situation.”

Biden also spoke with Netanyahu about Iran and Hezbollah’s potential retaliation, given that both have promised revenge for the strikes in Lebanon and Iran on Tuesday. Israeli forces claimed responsibility for an airstrike in Beirut, Lebanon, on Tuesday which successfully killed a high-level Hezbollah commander, just hours before the separate strike in Iran.

The two world leaders discussed joint U.S.-Israeli military operations that would stage a defense in the event of an attack, and U.S. Secretary of Defense Lloyd Austin informed his Israeli counterparts on Thursday about U.S. force posture changes in the Middle East, according to Reuters and Axios.

Biden told Netanyahu during their Thursday phone call, however, that should Israel stage a similar operation as it did earlier this week, he shouldn’t expect the U.S. to come to its defense, one U.S. official told Axios.

“I had a very direct meeting with the prime minister today. Very direct,” Biden told reporters on Thursday evening following his call with Netanyahu. When asked whether Haniyeh’s death would impact ceasefire talks, Biden said “It’s not helped.”

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