The Israeli military said Tuesday that four Israeli soldiers had been killed and several more wounded after militants blew up a building where the troops were operating in the southern Gaza city of Rafah.

Some of the soldiers were in critical condition after the attack on Monday, the military said. Kan, Israel’s public broadcaster, said that five soldiers had been hospitalized, and that two were in intensive care.

The Qassam Brigades, Hamas’s military wing, said in a statement that it had booby-trapped the building where the soldiers were operating. “Our fighters were able to blow up a house rigged with explosives where Zionist forces had fortified themselves inside,” it said.

The apparent ambush targeted an Israeli reconnaissance unit that was scouting what the soldiers thought was a tunnel shaft inside a three-story building, according to Kan. Israeli forces in Gaza have been focusing on destroying tunnels used by Hamas militants.

After the explosives were detonated, Hamas forces attacked with mortar fire as Israeli forces tried to evacuate the dead and wounded, according to both the militant group and the Israeli military.

Fighting in Rafah has raged on and off since early May, when Israeli soldiers moved into the southern city despite strong opposition from the international community. For months, Rafah had housed more than half the residents of Gaza. Israeli forces had directed people to take shelter there from fighting elsewhere in the territory.

Since the Israeli incursion into Rafah, many displaced Palestinians have fled to central Gaza, which in turn has seen clashes and heavy bombardment since Israel announced new military operations there last week. On Saturday, more than 200 Gazans were killed, according to health authorities, in the central city of Nuseirat during an Israeli military operation that freed four Israeli hostages.

In the eight months since Israel launched its offensive in Gaza in retaliation for the Hamas-led Oct. 7 attacks, a total of 298 of its soldiers have been killed, according to the Israeli military. The toll has been many times higher for Gazans: Local health authorities say more than 36,000 people have been killed, a tally that does not distinguish between combatants and civilians.

Myra Noveck contributed reporting.