TEL AVIV—At least 14 Israeli soldiers were killed across Gaza over the weekend as Hamas used guerrilla tactics against Israeli troops, who are now focused on killing the group’s leaders and dismantling its extensive tunnel network.  

On Saturday, four Israeli soldiers were killed by improvised explosive devices, and four more were killed by an antitank missile fired at their armored vehicle, according to Israel’s state-owned Army Radio. The names of the dead soldiers were confirmed by the Israeli military. Five additional soldiers were killed in fighting across the Strip on Friday, two of them by explosive charges, the military said.