In the worst fighting in years between Israel and the Palestinian Islamist group that runs Gaza… A 13-story residential block in Gaza collapsed after one of several dozen Israeli air strikes on Tuesday… as rockets also showered down into Israel.Gaza residents were sifting through debris... they had been warned to evacuate the area, according to witnesses, and there were no reports of casualties two hours after the lock collapsed. Shortly after the attack, Hamas said they would respond by firing rockets at Tel Aviv.Air raid sirens and explosions were heard around the city, and the skies were lit up by the streaks of multiple interceptor missiles launched towards the incoming rockets.Pedestrians ran for shelter, and diners streamed out of Tel Aviv restaurants as the sirens sounded. Thirty-one people were reported dead: 28 in Gaza and three in Israel. Even before a barrage sent in retaliation for the destruction of the tower block, which contained a civilian Hamas office, Israel reported that 480 rockets had been fired across the border by Palestinian militant groups.Israel said it had sent 80 jets to bomb Gaza, and dispatched infantry and armor to reinforce the tanks already gathered on the border, evoking memories of the last Israeli ground incursion into Gaza to stop rocket attacks, in 2014. The White House condemned this week’s rocket attacks.. At the U.S. State Department – A spokesman said Israel had a legitimate right to defend itself, but that the primary U.S. focus was on de-escalation.NED PRICE: "I will say that our message continues to be one of prioritizing de-escalation, urging calm, urging restraint on both sides."The Israeli military said many of the rockets fired from Gaza had fallen short and wounded Palestinians, and that Israel's Iron Dome air defenses had intercepted the bulk of those that made it across the border. The fighting between Israel and Gaza's armed factions was triggered by clashes between Palestinians and Israeli police at Jerusalem's al-Aqsa Mosque on Monday. Jerusalem - holy to Jews, Muslims and Christians - has been tense during the Muslim fasting month of Ramadan, with the threat of a court ruling evicting Palestinians from homes claimed by Jewish settlers adding to the friction.