FOR both Israelis and Palestinians, the third war between Israel and Gaza in six years may prove to be the most gruelling yet. Since the war started on July 8th over 500 people have been killed, all but 20 of them Palestinians. In a ground offensive, which started on July 17th, Israeli forces are focusing on four border areas along a strip 40km (25 miles) long, seemingly to destroy tunnels used by Hamas to launch attacks in Israel and to fortify its border against Israeli incursions. But most of the victims have been Palestinian civilians, including many children. In the worst violence to date on July 20th Israel attacked Shujaiya, a tightly packed residential suburb five minutes’ drive east of Gaza City that has long been a stronghold for an array of militants. The shelling killed66 Palestinians in one day; 13 elite Israeli soldiers died in the fighting of an ensuing ground offensive. Footage from the scene showed bodies of Palestinians, many of them women and children, strewn across the streets. Gazans have limited options as to where to flee: more than 80,000 people have sought shelter in UN schools.

On July 21st Israel’s defence minister, Moshe Yaalon, said the mission to destroy tunnels should be over in two to three days. But Binyamin Netanyahu, the prime minister, has warned that the offensive will continue until Israel has achieved its aims. These are said to include the destruction of rocket-launchers and command centres. But many of these lie concealed among and below civilian infrastructure in the heart of Gaza City and the mission looks set to draw Israel ever deeper into the heart of Gaza's teeming population centre.

Despite being besieged and the rising death toll, Hamas and fellow Islamists show no sign of changing course. They continue to launch over 100 rockets at Israel every day, targeting towns and cities from south to north. Hamas has launched drones for the first time and militants have repeatedly infiltrated Israel by sea and tunnel, sometimes to deadly effect. Over the weekend of July 19th-20th Hamas killed 18 Israeli soldiers, almost double Israel’s toll during the three weeks of Operation Cast Lead, hithero the biggest Israeli assault on Hamas in Gaza, in 2008-2009. In contrast to the resistance Israel’s forces encountered then, Israeli soldiers speak of fighting a force ambushing them with anti-tank missiles from fortified underground bunkers.