Oct. 21, 2025, 4:40 AM EDTBy Matt BradleyTEL AVIV — Hamas has violently sought to reassert its authority over the Gaza Strip in the wake of the Israel military’s partial withdrawal, but questions remain over the group’s future and efforts to rebuild.Since the ceasefire came into effect a week ago, the militant group has deployed armed police officers on streets from where Israeli forces have withdrawn, clashed with rival clans, directly fired upon and killed Israeli troops in multiple incidents, and staged at least one public execution of suspected collaborators. As Hamas continues to demonstrate its presence, Israeli security officials and experts on Gaza agree it has been badly diminished but not thoroughly destroyed, and will count with new recruits propelled to join after tens of thousands of Palestinian civilians were killed by Israeli fire. Assessments of Hamas’ strength are crucial to the negotiations around the group’s disarmament — an important stipulation in the American-brokered ceasefire deal that halted the war. So far, the group has refused to give up its weapons.“Hamas was damaged very severely in its military capabilities, but I think it will be fair to say that it wasn’t crushed,” said Shalom Ben Hanan, a fellow at the International Institute for Counter-Terrorism at Israel’s Reichman University and a nearly 30-year veteran of the Israeli Security Agency, also known as Shabak or Shin Bet. “Maybe the threat isn’t in the days to come or the nearest future. But their potential is still there.”Hamas militants with the Qassam Brigades in Deir el-Balah, central Gaza, on Monday.Bashar Taleb / AFP via Getty ImagesHanan said the group still commands about 15,000 to 25,000 fighters — an estimate he said was based on his regular briefings from serving Israeli security officials. According to an Israeli military official, who asked for anonymity to speak openly about the Israeli military’s internal assessment, about 10,000 to 20,000 commandos remain at Hamas’ disposal.Giora Eiland, the former director of Israel’s National Security Council and the former head of the planning department of the Israel Defense Forces, said Hamas lost about 20,000 fighters during two years of war — an estimate he also bases on conversations with serving security officials.A Hamas militant stands guard in Khan Younis on Friday, during a search for the bodies of hostages killed after the Oct. 7, 2023, attack.ReutersBut the group will have little trouble reconstituting its manpower, Eiland said, and security officials believe Hamas has been recruiting new fighters throughout the war even under fire.“It is easy for Hamas to regain power and it is very easy for them to recruit more and more people to replace those who were killed,” Eiland said.Hamas wrested power from the more secular and internationally recognized Fatah party in 2007 after winning legislative elections the previous year. The Islamist group, which the United States, Israel and many other countries classify as a terrorist group, does not recognize Israel’s right to exist and launched the Oct. 7, 2023, attacks in part to stall normalization efforts in the Arab world. Militants in Khan Younis, southern Gaza, in February.Abed Rahim Khatib / dap via APIsrael’s ensuing offensive has flattened much of the enclave, killed tens of thousands of civilians and engendered the kind of anger that could create thousands of potential recruits. “Although we will be speaking about young people with less military experience, they still have no doubt lots of competence and enough personal weapons like small arms and RPGs,” Eiland said, referring to rocket-propelled grenades.Tens of thousands of Palestinians have been killed and maimed in the war; a United Nations commission said in September that Israel is committing genocide against Palestinians in Gaza. Famine was officially declared in August in part of northern Gaza, including Gaza City, by the world’s leading authority on hunger. The war has also inflicted significant damage on Hamas’ supplies of its heaviest weapons and its weapons manufacturing capabilities, as well as on its senior leadership.The Israeli military official said that as many as 90% of the group’s rockets have been destroyed, and Israel has succeeded in frustrating Hamas’ ability to rebuild that lost heavy firepower.“Very important is the manufacturing sites, the smuggling routes and so on,” the military official said. “It’s not just taking away the fish, it’s taking away the rod.”All of the experts agreed that Hamas’ vast tunnel system remains its greatest strength and Israel’s greatest challenge.Eiland estimated that 70% to 80% of Hamas’ tunnels remain intact, with much of the surviving network unknown to Israel’s military.In a statement last week, Israeli Defense Minister Israel Katz said the IDF would turn its attention to destroying the remaining tunnel network as part of the process of disarming Hamas. The IDF said it had been working to dismantle a part of the tunnel network when some of its soldiers came under fire Sunday.A Hamas militant in Gaza City on Wednesday.Ahmad Salem / Bloomberg via Getty ImagesThe group’s political power and popularity — key components in its ability to recruit, rebuild its weapons and suppress its rivals — have been badly damaged. Even if Gazans are enraged at Israel for killing nearly 70,000 Palestinians during the war, Hamas still takes part of the public blame.“Politically is where Hamas is really in shambles,” said Ahmed Fouad Alkhatib, head of the Atlantic Council’s Realign for Palestine project, whose family is from the Gaza Strip. “They don’t really have a political program. They don’t really have a compelling agenda in Gaza.”But unlike the Islamic State terrorist group, or ISIS, and Al Qaeda — two terror groups whose power has been checked by the U.S.-led war on terror over the past quarter-century — Hamas presides over a true geographic constituency.“It is not a terrorist organization that came from nowhere and managed to take control over a certain area by spreading fear and terror,” Eiland said. “Hamas is the authentic representative of the people of Gaza.”Outside Gaza, Hamas also takes credit for turning global opinion against Israel, Alkhatib said.“Hamas feels that this shift is something that they alone brought about,” he said. “And Hamas ties that to its strategic picture on the ground.”Matt BradleyMatt Bradley is an international correspondent for NBC News based in Israel.