Israel pounded Hamas targets in the Gaza Strip for the fifth straight day since the fighters' audacious attack, as the death toll spiralled into the thousands and Prime Minister Benjamin Netanyahu set up an emergency government.Opposition leader Benny Gantz, a centrist former defence minister, was brought in to join veteran right-winger Netanyahu, setting aside political differences that have sparked mass protests.The development came after Israeli forces sweeping battle-torn southern towns said a total of 1,200 people, mostly civilians have been killed in the fighters' onslaught.In Gaza, officials reported more than 1,000 people killed in Israel's sustained campaign of air and artillery strikes on the crowded Palestinian enclave, sending black smoke billowing into the sky and razing entire city blocks.The UN said 11 of its staff had been killed in Gaza since Saturday, while the International Red Cross and Red Crescent societies said it had lost five of its members.In the occupied West Bank, at least four Palestinians were killed when armed Israeli settlers attacked a town south of Nablus, taking the death toll to 29, the Palestinian health ministry said.The crisis, dubbed "Israel's 9/11", saw Netanyahu strike a political deal with Gantz and pledge to freeze for now his government's judicial overhaul plan that has sparked unprecedented mass protests.Opposition leader Yair Lapid has not joined the temporary alliance, although the joint statement said a seat would be "reserved" for him in the war cabinet.As the war has raged, fears mounted in Israel for the fate of at least 150 hostages — mostly Israelis but also including foreign and dual nationals — held in Gaza by Hamas.The group has claimed that four captives died in Israeli strikes and threatened to kill other hostages if civilian targets are bombed without advance warning from Israel.Concern rose over the worsening humanitarian crisis in war-torn Gaza, where Israel had levelled over 1,000 buildings and imposed a total siege, cutting off water, food and energy supplies for 2.3mn people.The enclave's sole power plant shut down Wednesday after running out of fuel, Gaza's electricity provider said.More than 260,000 Gaza residents have been forced from their homes, a UN aid agency said, with secretary-general of the world body, Antonio Guterres, voicing fears of a deterioration in an already dire humanitarian situation.The European Union called for a "humanitarian corridor" to allow civilians to flee the enclave's fifth war in 15 years.Arab League foreign ministers meeting in Cairo called for aid to be allowed into Gaza "immediately".Israel appeared to be readying for a possible ground invasion of Gaza, but faces the threat of a multi-front war after also coming under rocket attack from fighter groups in neighbouring Lebanon and Syria.Israel again struck targets yesterday in southern Lebanon, an area controlled by Hezbollah.Biden, who has diverted an aircraft carrier battle group to the eastern Mediterranean, has warned Israel's enemies — state or group — not to get involved.A first US aircraft has delivered "advanced armaments" to southern Israel's Nevatim Airbase, the Israeli army said.Israel has been badly shaken by the deadliest attack since its creation in 1948 and the intelligence failure that allowed more than 1,500 fighters to storm through the Gaza security barrier in their co-ordinated land, air and sea attack on the Jewish Sabbath.The US State Department said at least 22 US citizens had been killed, as Secretary of State Antony Blinken headed to Israel in a show of solidarity.Israeli forces have retaken more than a dozen southern towns near Gaza after days of gruelling street battles that have left the bodies of at least 1,500 Hamas fighters strewn in the streets.Army spokesman Jonathan Conricus said they had discovered "a staggering 1,200 dead Israelis" — most of them civilians — as they went house to house.The army later reported 169 fallen Israeli soldiers.Troops have encountered and killed several holdout Hamas fighters, said Israeli military spokesman Daniel Hagari, including 18 yesterday.Heavy bombardment again rained down on Gaza, where the sky was blackened and Hamas said at least 30 people were killed in overnight strikes.Rubble, burnt out cars and broken glass covered roads in Gaza City, where bombs struck the Hamas-linked Islamic University.Also targeted were residential buildings, mosques, factories and shops, said Salama Marouf of the Gaza government's media office.Gaza resident Mazen Mohamed, 38, said his terrified family had spent the night huddled together as explosions shook the area, before emerging in the morning to assess the total devastation of their neighbourhood."We felt like we were in a ghost town, as if we were the only survivors," Mohamed said.Medical supplies, including oxygen, were running low at Gaza's overwhelmed Al-Shifa hospital, said emergency room physician Mohamed Ghonim.Unrest has flared in the occupied West Bank, where protests have been held in solidarity with Gaza and 27 Palestinians have been killed in clashes since Saturday.Frantic diplomacy has continued as international and regional powers sought to prevent a wider conflagration in the Middle East.