News desk :Over 500 Palestinians, mainly civilians and children have been killed since the Israeli rampage began 13 days ago, Gaza’s health ministry says.Twenty Israelis – 18 of them soldiers – have died, Israel admitted.Sunday was the deadliest day since the start of Israel’s offensive, with 13 Israeli soldiers and more than 100 Palestinians killed.Two of the soldiers killed were American citizens, US state department spokesperson Jen Psaki said.Sunday’s death toll for Israel’s military is higher than that sustained during the entire three-week duration of Israel’s last ground offensive in Gaza in 2008-2009.Israel says it has killed at least 120 Palestinian since Thursday night when it launched a ground offensive, the second phase of a military operation that began on 8 July.The deaths of so many soldiers on a single day will shock Israeli society, the BBC’s Chris Morris reports from southern Israel.Hamas said on Sunday evening that it had captured an Israeli soldier, prompting celebrations on the streets of Gaza and West Bank.However Israel’s UN ambassador Ron Prosor denied the claim, saying “those rumours are untrue”.The UN says 83,695 people have now been displaced in Gaza and that the figure is “rising all the time”.There were scenes of panic in Shejaiya, with thousands of residents fleeing.The fact that the battle has moved into a heavily populated urban area means that the civilian death toll will rise markedly. With it will come added pressure from outside to end the operation once and for all.Meanwhile Israeli tanks have shelled a hospital in the central Gaza Strip, killing at least five people and wounding another 15.Al Jazeera’s Stephanie Dekker, reporting from Gaza, said according to early reports the third floor of the al-Aqsa Hospital in Deir al-Balah had been hit by at least three tank shells.The hospital is the third to be hit by Israeli tank fire since Israel launched its ground offensive in Gaza.