The US has discussed brokering an aid corridor for civilians in Gaza as Israel’s air force continued to pound the territory. The Israeli death toll from an attack by Hamas militants, the deadliest in the country’s history, reached 1,200 people. The Palestinian health ministry in Gaza said that 974 people were killed and more than 5,000 wounded after Israeli attacks on the area. The US national security adviser, Jake Sullivan, said on Tuesday that talks on safe passage for civilians in Gaza were being held with Israel and Egypt. “We are focused on this question. There are consultations going on. But the details of that are something that are being discussed among the operational agencies and I don’t want to share too much of that publicly at this time.” The US secretary of state, Antony Blinken, was due to arrive in Israel on Thursday to discuss support in the war, in which 14 Americans have been killed and several taken as hostages. There have been pleas from humanitarian groups and EU officials for the creation of corridors to allow aid into Gaza and warnings that hospitals overwhelmed with wounded people were running out of supplies. The head of the Palestinian energy authority told local radio on Wednesday morning that Gaza’s sole power plant had only another 12 hours of fuel remaining. Israeli officials declared a “complete siege” of Gaza days after an attack by Hamas militants on towns bordering the territory. The Gaza Strip is a densely populated area housing more than 2.3 million people, with infrastructure already weakened after a 16-year blockade by Israel and a closure of Gaza’s southern border with Egypt. The Rafah border crossing into Egypt remained closed, after airstrikes on the area on Tuesday. Egypt routinely shuts the crossing, the only way out for millions of civilians. Cairo has so far declined to reopen the border to allow safe passage for civilians, despite sending a line of aid trucks to the border before the airstrikes. The World Health Organization (WHO) said there had been 11 attacks on Gaza healthcare sites in the first 36 hours of the conflict. “There is an urgent need to establish a humanitarian corridor for unimpeded, life-saving patient referrals and movement of humanitarian personnel and essential health supplies,” the WHO said. On Saturday, the morning of a Jewish holiday, the militant organisation Hamas launched a surprise attack from the Gaza Strip, with gunmen crossing the border, raiding Israeli cities and gunning down civilians in their homes, cars and at a desert music festival. As many as 150 hostages are believed to have been taken. Amid mounting expectations that Israel will launch a ground invasion of Gaza within days, the air force continued to batter the enclave with deadly strikes late on Tuesday, using dozens of fighter jets to hit more than 70 targets, according to Israeli military officials. Lt Col Jonathan Conricus, a spokesperson for the Israel Defence Forces (IDF), said on Wednesday morning that 300,000 reservists had been sent south, close to Gaza, and were getting ready “to execute the mission we have been given by the Israeli government … to make sure that Hamas, at the end of this war, won’t have any military capabilities by which they can threaten or kill Israeli civilians”. In Gaza’s al-Rimal neighbourhood, Palestinian civil defence forces pulled Abdullah Musleh out of his basement together with 30 others after their apartment building was flattened. “I sell toys, not missiles,” the 46-year-old said, weeping. “I want to leave Gaza. Why do I have to stay here? I lost my home and my job.” The Israeli military has issued warnings to civilians to evacuate whole neighbourhoods before inflicting devastation, although Palestinian residents of Gaza say they are forced to flee with no safe place to run to. The UN humanitarian agency OCHA described a “mass displacement,” in the Gaza Strip, with more than 263,000 people fleeing their homes. It said that number was expected to rise further. On Tuesday, the military told residents of the al-Daraj neighbourhood to evacuate. New explosions soon rocked it and other areas, continuing into the night. One blast hit Gaza City’s seaport, setting fishing boats aflame. “There is no safe place in Gaza right now. You see decent people being killed every day,” the Gaza journalist Hasan Jabar said after three Palestinian journalists were killed in the bombardments in Al Rimal. “I am genuinely afraid for my life.” Sporadic fighting continued in southern Israel on Tuesday night, with a group of militants entering an industrial zone in Ashkelon, sparking a gun battle with Israeli troops, the military said. Three militants were killed, and troops were searching the area for others. In East Jerusalem, the Israeli police said they shot and killed two Palestinians who had thrown fireworks at security forces in the Silwan neighbourhood. There is rising concern about an increasing use of live fire by Israeli forces at checkpoints and during clashes with Palestinian young people across the West Bank. The organisation Defense for Children Palestine, which documents harm to children across the occupied Palestinian territories, said before the shooting in East Jerusalem it had recorded at least five separate incidents of children being shot and killed on the West Bank, all with gunshot wounds to their abdomen, chest, or head. The Israeli military spokesperson Conricus said early on Wednesday that the Israeli death toll since Saturday stood at 1,200, with more than 2,700 wounded. The already “unimaginable” figure would increase, he said, with the overwhelming majority of the dead civilians. The rising numbers were the result of new discoveries of victims rather than fresh fighting, he said. Conricus added that Israeli forces had regained control in the south and rebuilt the barriers along the border that Hamas breached to launch Saturday’s attack. About 150 people are believed to be held captive by militants in Gaza, with Hamas threatening to start executing its hostages if Israel carries out airstrikes on civilians without giving “prior warning”. Israel said on Tuesday that it had recovered the bodies of more than 1,500 Hamas fighters inside Israel, giving the clearest indication yet of the scale of the weekend’s assault.