GAZA — Nearly half of Hamas’ military battalions in northern and central Gaza have rebuilt some of their fighting capabilities despite more than nine months of Israel’s brutal offensive, according to analyses by the American Enterprise Institute’s Critical Threats Project, the Institute for the Study of War and CNN.

Israeli Prime Minister Benjamin Netanyahu, who faces growing international pressure to agree to a ceasefire and hostage release deal in Gaza, has repeatedly said that Israeli forces are nearing their stated goal of eliminating Hamas and destroying its military capabilities. Addressing a joint meeting of Congress on July 24, he said: “Victory is in sight.”

But forensic analyses of Hamas’ military operations since it led attacks against Israel on October 7, which draw on Israeli and Hamas military statements, footage from the ground and interviews with experts and eyewitnesses, cast doubt on his claims.

Israel has dealt a heavy blow to the militant group: senior Hamas figures have been killed and the ongoing offensive has reduced what once was a professional fighting force into a guerrilla army.

Hamas’ political leader, Ismail Haniyeh, was assassinated last week in Tehran in an attack Iran has blamed on Israel. Israel has not claimed responsibility, but said a day later that Hamas’ top military commander, Mohammad Deif, was killed in a July 13 airstrike in Gaza — a report Hamas has neither confirmed nor denied.

And yet, the research, which covers Hamas’ activities up until July, shows that the group appears to have made effective use of dwindling resources on the ground. Several units have made a comeback in key areas cleared by the Israeli military after pitched battles and intensive bombardment, according to the new analyses, salvaging the remnants of their battalions in a desperate bid to replenish their ranks.

“The Israelis would say that they cleared a place, but they haven’t fully cleared these areas, they haven’t defeated these fighters at all,” said Brian Carter, Middle East portfolio manager for Critical Threats Project (CTP), who led the joint research with the Institute for the Study of War (ISW) into patterns of Hamas and Israeli military activity.

“(Hamas) are ready to fight and want to fight.”

The Israel Defense Forces and Israeli Prime Minister’s Office have not responded to CNN’s requests for comment on the findings.

CNN combed through thousands of claims by the Qassam Brigades and the Israeli military, and geolocated scores of videos showing battles in Gaza in recent months, to verify and analyze the findings by the DC-based think tanks.

Interviews with Israeli military and Palestinian civilian sources on the ground in Gaza also helped corroborate trends shown in their research.

US military experts interviewed for this report said that Israel's prosecution of the war, defined by a heavy-handed bombing campaign, and the absence of a post-war plan has helped trigger Hamas' resurgence.

There has been evidence of that resurgence in key flashpoints. In Jabalya refugee camp, Israel said it returned in May to “fierce” resistance from three Hamas battalions, despite having devastated the area in a nearly three-month bombing campaign in the fall. And Israel has staged four incursions in Gaza City’s Zeitoun neighborhood, according to the analyses.

“If the Hamas battalions were largely destroyed, Israeli forces wouldn’t still be fighting,” said retired US Army Col. Peter Mansoor, who helped oversee the deployment of an additional 30,000 US troops to Iraq in 2007 – a counterinsurgency strategy known as “the surge.”

Mansoor served as executive officer to retired Gen. David Petraeus, the head of US-led multinational forces at the time.

“The fact that they’re still in Gaza, still trying to rout out elements of the Hamas battalions shows me that Prime Minister Netanyahu is wrong,” he added. “The ability of Hamas to reconstitute its fighting forces is undiminished.”

US military experts have repeatedly cited the surge as an effective blueprint for Israel. Its architect, Petraeus, advised Israel in an article in Foreign Affairs to “sharply distinguish” Hamas from civilians to “prevent irreconcilable Hamas elements from reconstituting.” He also called on Israel to support an alternative government in Gaza.

Biden administration officials, including Secretary of State Antony Blinken, have criticized Israel for not engaging in post-war planning.

Israel says that it has killed half of Hamas’ commanders and over 14,000 combatants in Gaza. Hamas disputes those figures, though it has not offered a casualty count. According to Gaza’s Ministry of Health, nearly 40,000 people have been killed and more than 91,000 injured, since the war began.

Around 1,200 people were killed in the Hamas-led attacks on Israel on October 7, and more than 250 abducted.

“Everywhere Hamas rears its head, we will enter,” said one high-ranking Israeli army officer, who CNN is not naming because he was not authorized to speak. “Can this ping pong stay forever? No. Our society is not built for this. And neither is the international community.”

The officer compared the campaign in Gaza to “a marathon runner who doesn’t know where the stadium is. You run and you don’t know if you’re headed in the right direction.”

In May, Secretary of State Antony Blinken warned that the upcoming Israeli offensive in Rafah, where around 1.5 million internally displaced people had settled, could incur an “incredibly high cost to civilians” and leave Israel with an “enduring insurgency.” Without a plan to replace Hamas, Blinken said, Gaza would be left with a “vacuum” likely to be filled “by chaos, by anarchy, and ultimately by Hamas again.”

In a news conference in early July, US President Joe Biden recounted his meeting with Netanyahu at the outset of the war, saying that he had drawn parallels between al Qaeda’s attack on the United States on September 11, 2001, and the Hamas-led attacks on Israel on October 7.

“Don’t make the same mistake America made after (al Qaeda leader Osama) bin Laden,” he said he warned Netanyahu. “There’s no need to occupy anywhere. Go after the people who did the job.”

In parts of the wasteland of northern Gaza, Hamas members in plainclothes supervise blown out marketplaces, repurpose burnt buildings into sites for militants and civil servants, and hide their weapons under the detritus, sources on the ground in Gaza told CNN.

“Hamas’ presence in northern Gaza is stronger than you can imagine,” said one Palestinian who recently fled the region, and who asked to remain anonymous for fear of reprisals.

“They’re among civilians. It helps them rebuild their forces,” said the man, who lost nearly 40 members of his family in an Israeli airstrike.

Another Palestinian said he saw a Hamas-run makeshift jail in Gaza City holding Palestinians accused of looting. “To punish thieves, they’re tying up their hands and blindfolding them,” he said. “They turned a charred room into a jail cell, and they placed a bucket there for their toilet needs.”

Israel pummeled this part of Gaza – the territory’s most populous at the time – for the first three months of its offensive.

Hundreds of large munitions laid waste to Gaza City and its surrounding neighborhoods and refugee camps, prompting nearly 80% of the population to seek the relative safety of southern Gaza. By the end of December, Israeli firepower had killed over 21,000 Palestinians, according to Gaza’s Ministry of Health. More than half of the dead were women and children, according to the United Nations.

On January 7, the Israeli military said it had dismantled Hamas’ command structure in northern Gaza.

Within days, however, there were reports of attacks on Israeli patrols in eastern parts of Gaza City. Videos in the weeks that followed showed Hamas fighters apparently emerging from beneath the rubble, likely from the sprawling tunnel network that crisscrosses the territory.

“We began to notice a resurgence in Hamas less than a week after Israel withdrew from northern Gaza in January,” said Carter from CTP. “We saw this effect continuing throughout the strip ... This has been the defining process from the Hamas battalions.”

Hamas has boasted of recruiting “thousands” of new fighters since the war began.

“They (Israel) have certainly killed a lot of Hamas fighters, but they’re still out there, and they’re going to be recruiting like crazy based on the kinds of things that Israel has done,” said Emily Harding, director of the Intelligence, National Security and Technology Program at the Center for Strategic and International Studies (CSIS) in Washington, DC.

At least one Israeli source close to the military agrees with Hamas’ estimate, though he argues that it will be much more difficult for Hamas to replace dead commanders.

“Recruitment started three or four months ago, and they got a few thousand. I don’t know exactly how many,” said one retired high-ranking Israeli officer. “Hamas’ biggest difficulty is not at the level of soldiers but at the level of commanders, some (of) which are not easy to replace.”

Despite their degradation, the Qassam Brigades continue to draw Israeli forces into repeated cycles of fighting.

“It’s a game of whack-a-mole,” said Robert Pape, a professor of political science at the University of Chicago and the author of four books about counterinsurgency. “Israel tells the population to go to the center, to the south, and then a large number ultimately do ... They keep moving these people around ... and guess who moves with the population? Almost all Hamas fighters.”

“Hamas, the personnel, the fighters and leaders and supporters are embedded deeply within the population,” said Pape. “They’ve built bonds with this population going back decades.”

The analysis by ISW and CTP suggests that reconstitution has happened in two distinct ways. Some Qassam Brigades units have regrouped, merging severely degraded cells to create combat effective battalions; others have regenerated, recruiting new fighters and manufacturing new weapons from the explosive material left behind by Israeli forces.

With their camps largely destroyed, the Qassam Brigades are unlikely to put their new fighters through meaningful training.

The original platoons have been severely diminished, forcing Hamas to rely on guerilla tactics, laying booby traps and staging ambushes, typically when Israeli troops have launched an incursion into the center of a camp or neighborhood, geolocated videos show.

The cycle of resurgence was laid bare in northern Gaza’s Jabalya refugee camp, which was all but leveled by some of Israel’s heaviest munitions in the first phase of the war.

After three months of heavy bombardment, Israel declared the three battalions operating there “dismantled.” Less than six months later, it said the units were reconstituting. Israeli troops staged another incursion into the camp, and the military said it faced some of the “fiercest fighting” since the start of the entire war.

When Israeli forces withdrew from Jabalya on May 31, analysis of the three battalions suggested they were degraded but not destroyed.

“Israel is generating exactly the kind of additional political anger, the additional grief, the additional emotion that will lead additional people to become fighters,” said Pape.

“The actual strategic power of Hamas is growing,” he said. “The power of Hamas is in its power to recruit.”

Public sentiment about Hamas in Gaza is difficult to gauge, but there are signs of festering resentment.

A survey by the Arab Barometer conducted just weeks before the war began found that the majority of Gazans polled were frustrated with the group’s governance of the territory.

When Palestinians in Gaza criticize Hamas, they express their disgruntlement in hushed tones for fear that a member of the group may be within earshot. “They gave Israel an excuse to destroy us,” said one person requesting anonymity, referring to the Hamas-led attacks on October 7.

"The anger and frustration comes up much more frequently now than it did in my last trip in,” said former CNN correspondent and president of the humanitarian organization INARA, Arwa Damon, who was in Gaza in June as an aid worker for the second time since the start of the war. “People say this quite openly: ‘everyone is trading in our blood.’”

“But the number one focus of anger is Israel.”

Many Palestinians in Gaza speak about trying desperately to give a wide berth to Hamas members – known pejoratively as “the green guys” – in their midst. But the massive blast radius of Israel's heavy munitions and its frequent targeting of displacement camps and hospitals where it claims Hamas militants hide makes that a nearly impossible task.

“We are tired and exhausted. Look at how the people have been obliterated. It is enough,” said Riham al-Agha, holding her young daughter’s hand as she fled the destruction left by an Israeli strike in the southern Gaza city of Khan Younis in late July.

Addressing Hamas, she told a journalist working for CNN in Gaza: “You are staying underground and leaving people here to be killed.”

“How much longer should we keep evacuating from one area to another? We have evacuated 10 times since October 7,” she said. “We want a solution. We are losing our children. It’s enough.”

The absence of a governing body and Israel’s throttling of humanitarian aid to a relative trickle exacerbates the desperation. Looting and sporadic fighting between clans is on the rise, according to sources on the ground, and the UN reports that infectious diseases — including polio, which had been previously eradicated in Gaza — are reported to be spreading rapidly.

“The growing lawlessness, the growing anarchy that feels very deliberately orchestrated, is going to allow Hamas or its reincarnation to reemerge,” said Damon. “Once these bombs stop falling, people are going to be desperate for rule of law.”

Proponents of the 2007 “surge” strategy in Iraq lay out three main principles on counterinsurgency: clear the territory of insurgents, hold on to the territory and build relations with local communities.

It’s a strategy that is nearly impossible to adapt in Gaza, experts say. Harding, of the CSIS, said that to hold territory, “you put troops in a forward operating base, you get to know the locals, you build trust with the locals so that they actually report on the guys who are coming back insurgents.”

“That was never going to happen in Gaza.”

In the absence of a lasting military solution, some commentators say a political resolution to the long-running conflict is more pressing than ever before.

“The only way this conflict will end is with a Palestinian state,” said retired Col. Mansoor. “But the Palestinians, for their part, need to realize that Israel’s not going anywhere ... right now, you have an Israeli government that refuses to countenance any sort of state for the Palestinians.”

“This conflict will only end with a political solution. It won’t end with a military victory.” — CNN