Palestinian militants carried out one of the deadliest single attacks on Israeli soldiers since the ground invasion of Gaza began, killing at least nine in an ambush in a dense urban neighborhood, the military said on Wednesday, a sign of the stiff resistance Hamas still poses despite more than two months of devastating bombardment.

The ambush came after repeated recent claims by the Israeli military that it had broken Hamas’ command structure in northern Gaza, encircled remaining pockets of fighters, killed thousands of militants and detained hundreds more.

The tenacious fighting underscores how far Israel appears to be from its aim of destroying Hamas — even after the military unleashed one of the 21st century’s most destructive onslaughts. Israel’s air and ground assault has killed more than 18,600 Palestinians, according to Gaza’s health officials. Gaza City and surrounding towns have been pounded to ruins. Nearly 1.9 million people have been driven from their homes.

The resulting humanitarian crisis has sparked international outrage. The US has repeatedly called on Israel to take greater measures to spare civilians, even as it has blocked international calls for a ceasefire and rushed military aid to its close ally.

Israeli troops are still locked in heavy combat with Palestinian fighters in and around Gaza City, more than six weeks after invading Gaza’s north following the militants’ October 7 attack.

Clashes raged overnight and into on Wednesday in multiple areas, with especially heavy fighting in Shijaiyah, a dense neighbourhood that was the scene of a major battle during the 2014 war between Israel and Hamas.

“It’s terrifying. We couldn’t sleep,” Mustafa Abu Taha, a Palestinian agricultural worker who lives in the neighborhood, said by phone. “The situation is getting worse, and we don’t have a safe place to go.”

The ambush took place on Tuesday in Shijaiyah, when troops searching a cluster of buildings lost communication with four soldiers who had come under fire, the military said.

When the other soldiers launched a rescue operation, they were ambushed with heavy gunfire and explosives.

Among the nine dead were Colonel Itzhak Ben Basat, 44, the most senior officer to have been killed in the ground operation, and Lieutenant Colonel Tomer Grinberg, a battalion commander.