Hamas threats to kill hostages could weaken group’s hand in negotiations

Hamas’s implied threat on Monday could be an attempt to widen the rifts in Israeli society over the captives and increase pressure on Isreal’s Prime Minister Benjamin Netanyahu to agree to a cease-fire deal.

But killing more hostages could cost the U.S. designated terrorist group one of the most powerful bargaining chips it has as it tries to negotiate for its own survival after months of punishing warfare.

After saying for days that Israel had killed the hostages with its bombing campaign in Gaza, Hamas issued a new statement Monday suggesting it had executed them and would do so again if Israel’s military attempted further rescue missions.

Without a negotiated end to the war, Hamas leader Yahya Sinwar and his fighters won’t be able to leave the tunnels in which they are hiding without risk of being killed by Israel. Instead, they will need to persevere as Israeli forces penetrate more deeply into Hamas’s subterranean lairs.

Hamas’s believed execution of six hostages last week sparked protests and a general strike by Israelis who want their government to agree to a cease-fire and hostage-return deal. But there are also many Israelis who view the killings as another reason the war must go on until Hamas is completely destroyed.

For Hamas, having fewer living Israeli prisoners also makes it harder to win the release of thousands of Palestinian prisoners held in Israeli jails—something Sinwar has used as a justification for the group’s Oct. 7 attack that killed over 1,200 people, mostly civilians, according to Israel, and abducted more than 240 civilians and soldiers.

Freeing Palestinian prisoners is also important to sustaining the group’s legitimacy after 11 months of war has destroyed most of Gaza and, according to local authorities, resulted in the deaths of more than 40,000 Palestinians. The figure doesn’t distinguish between civilians and combatants.

Of the remaining 97 hostages taken on Oct. 7 to Gaza, 33 of them have been declared dead by Israel. In talks with mediators, Hamas has said they may have no more than 30 living hostages in total, including 12 women, elderly or injured people, according to Arab mediators.

Hamas has managed to survive an 11-month-long offensive by a militarily superior foe. But as the Israeli military continues to expand its control, taking over key crossings and borders, dismantling tunnels and killing senior leaders, Hamas’s survival is under growing threat.

“This is an outcome of the chaotic situation that Hamas finds itself in," said Kobi Michael, a senior fellow at the Institute for National Security Studies, a security think tank in Tel Aviv, of the threat to execute more hostages. “Hamas cannot operate any more as an organized military."

Even so, Hamas’s goal in the war is simply survival. If Sinwar and others can achieve a cease-fire and emerge from hiding, they can claim victory and will likely be seen as the leaders of the Palestinian cause. In the absence of a cease-fire, Hamas could drag Israel into a prolonged occupation of Gaza that is likely to sap the strength of its military and prove unpopular among Israelis in the long term. Either way, the war has created a new generation of Palestinians who are openly hostile to Israel.

Israel says it has largely ended the Hamas’s ability to function as an effective military, although militants continue to fight Israeli soldiers. Hamas says it can no longer communicate within the Gaza Strip, and its leaders in Qatar have largely lost touch with those in the area, according to Arab officials.

Israel says Hamas militants have started moving into humanitarian zones, a sign that it has fewer places to hide. Last week, the Israeli army said it rescued a hostage after his captors had fled.

Israel announces killings of militants nearly daily. On Tuesday, the Israeli military said an airstrike killed eight Hamas members, including one who led an attack on an Israeli community on Oct. 7 when Hamas killed a father in front of his two young boys.

Hamas says it is able to quickly recruit new fighters, but they won’t have the same level of training as the ones who were killed.

“There’s no secret about the fact that Hamas has been weakened," said Mkhaimar Abusada, associate professor of political science at Al-Azhar University in Gaza and now based in Cairo. “But it hasn’t been weakened to the point that they are going to surrender."

The Israeli military is also taking greater control inside the strip, damaging the influence of Hamas as a civilian administrator.

Earlier this week, Israel facilitated the vaccination of thousands of children in Gaza against the polio virus. Gazans also say there is an increased Israeli presence in two major corridors that run across the strip, a reminder of the days before Israel withdrew from Gaza in 2005.

“I never thought we would see Israelis between us again, but here they are, they can come in and out any minute," said Badr Abu Yousef, a 29-year-old electrician in Gaza City.

Some Arab negotiators said they believe Hamas’s threats reflect growing disarray inside the organization. Hamas has told negotiators for months that it needed a pause in fighting to track and collect the hostages held by it and other groups.

On Monday, Hamas senior official Khalil al-Hayya said that Hamas’s armed wing lost contact with U.S.-Israeli citizen Hersh Goldberg-Polin, one of the six hostages killed, and his guards, after releasing a video of him in April.

But then on the same day the group released a video on its telegram channel saying it had recorded Goldberg-Polin’s final words.

“These conflicting messages will have great implications on the already complicated talks," said one Arab mediator. “Israel has always been suspicious of Hamas claims that they did not have information on all the hostages."

In Israel, Netanyahu’s government faces criticism from many Israelis for failing to agree to a deal and for failing to communicate a clear postwar plan for Gaza.

Israeli military officials have said the army has caused enough disruption to Hamas in Gaza, including killing its top two military leaders, and that the group can’t repeat the scale of attacks on Oct. 7.

Netanyahu has insisted that Hamas in Gaza be destroyed, militarily, and that Sinwar—who so far has successfully evaded Israeli forces—be killed.

“Killing Sinwar, of course, would be a huge victory, but it isn’t going to address, ultimately, the security problem inside Gaza," said Sanam Vakil, a Middle-East expert at the U.K.’s Chatham House think tank. “The failing of Israel’s strategy is that they’re not willing to think about any other solution besides a military one."

The Israeli military has become frustrated with Netanyahu’s demand in cease-fire negotiations that Israel retain control of the Netzarim and Philadelphi corridors. His critics allege the prime minister’s calculations are political: far-right members of his coalition have threatened to topple the government if he agrees to end the war. Polls show Netanyahu wouldn’t be re-elected if elections were held now.

But Netanyahu argues that pulling Israeli troops from Philadelphi, which divides Gaza from Egypt, and Netzarim, which cuts across the enclave, would allow Hamas to reconstitute, undermining his war aims.

Political analysts and mediators who talk with Hamas say the group is unlikely to agree to those cease-fire terms, which would see it give up hostages in return for circumstances that hasten the group’s demise.

“There is no doubt that the death of many Israeli prisoners made the card Hamas has weaker," said Istanbul-based Ibrahim Al-Madhoun, a political analyst close to the group. “But Hamas is not giving up."

— Abeer Ayyoub and Fatima AbdulKarim contributed to this article.

Write to Rory Jones at Rory.Jones@wsj.com and Summer Said at summer.said@wsj.com