Deadly Israeli airstrikes pounded the Gaza Strip on Tuesday and razed entire districts as the United Nations said Israel’s total siege of the Palestinian enclave is banned under international law. Gaza’s health ministry said the bombing had killed at least 830 people and wounded 4,250. The strikes intensified as night fell, shaking the ground and sending more columns of smoke and flames into the sky. It comes after Israel imposed a total siege on the Gaza Strip Monday, cutting off food, water and electricity supplies, and sparking fears of an increasingly desperate humanitarian situation. Hamas has threatened to execute the hostages if Israeli air strikes continued targeting Gaza residents without warning. Meanwhile, Volker Turk, the UN high commissioner for human rights, has said people’s dignity and lives had to be respected as he called for all sides to defuse the “explosive powder-keg situation”. “International humanitarian law is clear: the obligation to take constant care to spare the civilian population and civilian objects remains applicable throughout the attacks,” Turk said in a statement. The siege risk seriously compounding the already dire human rights and humanitarian situation in Gaza, including the capacity of medical facilities to operate, especially in light of increasing numbers of injured, the statement said. “The imposition of sieges that endanger the lives of civilians by depriving them of goods essential for their survival is prohibited under international humanitarian law,” Turk said. Any restrictions on the movement of people and goods to implement a siege must be justified by military necessity or may otherwise amount to collective punishment, the statement added. At the morgue in Gaza’s Khan Younis hospital, bodies were laid on the ground on stretchers with names written on their bellies. Medics called for relatives to pick up bodies quickly because there was no more space for the dead. A municipal building was hit while being used as an emergency shelter. Survivors there spoke of many dead. “No place is safe in Gaza, as you see they hit everywhere,” said Ala Abu Tair, 35, who had sought shelter there with his family after fleeing Abassan Al-Kabira near the border. Radwan Abu al-Kass, a boxing instructor and father of three, said he had been one of the last to evacuate his five-storey building in the Al Rimal district after the area came under attack. He finally left when a missile hit the building, which was destroyed by a bigger strike after he got out. “The whole district was just erased,” he said. Two members of Hamas’ political office, Jawad Abu Shammala and Zakaria Abu Maamar, were killed in an air strike in Khan Younis in southern Gaza, a Hamas official said. The Israeli military said they had been struck overnight. The Palestinian Foreign Ministry said Israeli strikes had since Saturday destroyed more than 22,600 residential units and 10 health facilities and damaged 48 schools. Four Palestinian journalists were killed in Israeli air strikes on Gaza City on Tuesday, media unions and officials have said. The latest deaths bring the number of Palestinian journalists killed in the fighting since Saturday to eight, the Palestinian Press Union said in a statement. Another union, the Gaza journalists’ syndicate, announced earlier “the martyrdom of three journalists in the Gaza Strip in the ongoing Israeli aggression”. The chief of Gaza’s Hamas-run government media office, Salameh Maarouf, identified the three as Said al-Taweel, director of Al-Khamisa news agency; press photographer Mohammed Sobboh, and Hisham Nawajhah, a correspondent for a Gaza news agency. They were killed in a strike while covering the evacuation of a residential building near Gaza City’s fishing port, Maarouf said, condemning Israel’s “criminal behaviour against journalists”. Members of the press were standing several dozen metres (yards) from the building after a resident received a telephone call from the Israeli army warning of an imminent strike, an AFP correspondent reported. Witnesses said the Israeli strike hit a different building, closer to where the journalists had been. Later in the day, the press union said the head of its committee of women journalists, Salam Khalil, was killed along with her husband and children when the family’s home in the northern Gaza Strip was hit in a “treacherous” Israeli bombing. Journalist Asad Shamlakh was killed on Sunday, the media office statement said, adding two cameramen were missing and 10 journalists were wounded. Three journalists were killed on Saturday, according to the Palestinian statement and the Committee to Protect Journalists. The New York-based media rights group said on Monday that Ibrahim Mohammad Lafi, a photographer, Mohammad Jarghoun, a reporter, and Mohammad El-Salhi had been shot dead in different incidents. “We call on all sides to remember that journalists are civilians and should not be targeted,” Sherif Mansour of the Committee to Protect Journalists said in a statement. “Accurate reporting is critical during times of crisis and the media has a vital role to play in bringing news from Gaza and Israel to the world. ” Separaterly, the ongoing UN investigation into alleged human rights violations in the Israeli-Palestinian war said there was “already clear evidence that war crimes may have been committed” since Saturday’s surprise Hamas assault. “All those who have violated international law and targeted civilians must be held accountable for their crimes,” said the Commission of Inquiry. The COI, the highest-level investigation that can be ordered by the UN Human Rights Council, was set up in May 2021 to investigate all alleged violations of international humanitarian and human rights law. The independent commission said it had been “collecting and preserving evidence of war crimes committed by all sides” in the current conflict. “Taking civilian hostages and using civilians as human shields are war crimes,” it said. It is also “gravely concerned” by Israel’s total siege on the Gaza Strip, “which will undoubtfully cost civilian lives and constitutes collective punishment”. The United Nations humanitarian office said that nearly 200,000 people or nearly a tenth of the population, have fled their homes in Gaza since the start of hostilities and is poised for shortages of water and electricity due to a blockade. “Displacement has escalated dramatically across the Gaza strip, reaching more than 187,500 people since Saturday. Most are taking shelter in schools,” Jens Laerke, OCHA spokesperson, told a Geneva briefing, saying further displacement was expected as clashes continue. A World Health Organisation spokesperson said it had reported 13 attacks on health facilities in the Gaza strip since the weekend and said that its medical supplies stored there had already been used up. The WHO, meanwhile, called for a humanitarian corridor to be established into and out of the Gaza Strip. “WHO is calling for an end to the violence… A humanitarian corridor is needed to reach people with critical medical supplies,” WHO spokesman Tarik Jasarevic told a press briefing in Geneva. Israeli air operations have struck residential buildings, including large tower blocks, as well as schools and UN buildings across Gaza, resulting in civilian casualties, the United Nations Human Rights chief said on Tuesday, citing information gathered by his office. European Union foreign policy chief Josep Borrell said he has invited the top diplomats from Israel and the Palestinian Authority to address an emergency meeting of the bloc’s foreign ministers. Borrell said Israel’s Foreign Minister, Eli Cohen, and his Palestinian counterpart, Riyad al-Maliki, were asked to participate in the hybrid video and in-person talks after the surprise Hamas assault. Earlier in the day, Israel said it had re-established control over the Gaza border and was planting mines where Hamas fighters had toppled the barrier during their weekend offensive, after another night of relentless Israeli air raids on the enclave.