Sixty Palestinians were killed Sunday in a heavy bombardment of a Gaza neighborhood and 13 Israeli soldiers were slain in clashes in the most intense day of fighting in Israel’s ongoing offensive against Hamas fighters, officials said.

The casualties brought the total number of Israeli military deaths to 18 since the armed forces launched a ground operation Thursday after days of airstrikes on the coastal strip, the Israeli military said. The Israeli death toll in the nearly two-week-old offensive is now higher than during the Israeli military’s 2009 incursion into Gaza, when 13 Israelis were killed.

Israel pummeled a neighborhood in east Gaza overnight Sunday, producing gruesome images of bodies in the streets amid masses of rubble. The Gaza Health Ministry said 60 Palestinians were killed in the fighting. In Gaza there are now more than 81,000 displaced people who are seeking refuge in 61 shelters run by the United Nations.

Thousands of panicked residents were pouring out of the area in mass flight Sunday morning. The scene at Shifa Medical Center, Gaza’s main hospital, was chaotic. Ambulance drivers reported great difficulty entering the east Gaza town called Shijaiyah, which bore the brunt of continuous fire.

After a brief lull at dawn, midmorning Sunday saw an increase of artillery and tank shelling. Explosions sounded closer to the center of Gaza City, and the sky was filled with Israeli drones witnessing the exodus of civilians.