The Pentagon’s top general offered a rare critique of Israel’s war strategy on Monday, warning Israeli troops’ failure to hold ground they had taken from Hamas in northern Gaza could have long-term effects.

“Not only do you have to actually go in and clear out whatever adversary you are up against, you have to go in, hold the territory and then you’ve got to stabilize it,” said Gen. C.Q. Brown, chair of the Joint Chiefs of Staff, drawing on his years in the Middle East.

Brown, who rarely chides Israeli forces, stressed that the Israeli tactic of pushing Hamas fighters out of one area and then leaving makes achieving lasting stability more difficult. Instead, he suggested, they are ceding ground for Hamas to return and undermine humanitarian efforts to help the population in Gaza.

In the weeks after Hamas’ Oct. 7 attack on Israel, the Israeli military launched a ground incursion into northern Gaza to root out Hamas fighters. After weeks of hard fighting, Israel said it had won the fight in the north of the enclave and pulled out all but a handful of troops.

Hamas fighters have since returned to areas of northern Gaza, forcing Israel to try and retake ground it had already won. The renewed clashes have called into question how long the fighting in Gaza will last, and whether the Israeli government’s goal of eradicating Hamas is achievable.

Reports over the past week have detailed fierce fighting in the densely-packed streets of Jabalia and renewed Israeli airstrikes on targets in the city as the fighting intensifies.

Brown, drawing on U.S. lessons in Iraq and Afghanistan, said Monday that after Israel “cleared they didn’t hold, and so that allows your adversary then to repopulate in areas if you’re not there.” Having to return to the same areas multiple times “does make it more challenging [for Israel] as far as being able to meet their objectives of being able to militarily destroy and defeat Hamas.”

The Israeli government has said it intends to dismantle Hamas, kill or capture its leadership, and rescue the roughly 130 Israeli hostages still held by the group.

Eight months into the war, Israel has met none of those objectives. Tensions within the Israeli government are growing, with calls for Prime Minister Benjamin Netanyahu to publicly lay out a plan for the war and its aftermath.

Israeli Defense Minister Yoav Gallant, who was slapped with an arrest warrant by the International Criminal Court on Monday, last week broke from Netanyahu’s right-wing government by rejecting the idea of a long-term Israeli occupation of Gaza after the war.

A stable, post-Hamas Gaza “will only be achieved with Palestinian entities taking control of Gaza, accompanied by international actors,” Gallant said. “I will not agree to the establishment of Israeli military rule in Gaza.”

Brown, in his comments on Monday, referenced the layered challenges of defeating Hamas.

“Hamas is not just an organization, it’s an ideology,” he said, alluding to how Hamas has governed the territory since 2005. “So you have to think about the overall piece to provide security not only for Israel, but in the region.”