There have been "clear violations of international law" in the Gaza Strip, the United Nations chief claimed on Tuesday, as he called for a humanitarian ceasefire so desperately needed aid could be delivered.
Speaking to the UN Security Council, Secretary-General Antonio Guterres said that Israel's increasing bombardment of Gaza and the hundreds of civilian deaths is "alarming" as he appealed "to all pull back from the brink before the violence claims even more lives spreads even farther".
Protecting civilians "is paramount in any armed conflict," he added.
Without naming Hamas, the UN chief stressed that "protecting civilians can never mean using them as human shields."
Mr Guterres also criticised Israel without naming it, saying "protecting civilians does not mean ordering more than one million people to evacuate to the south, where there is no shelter, no food, no water, no medicine and no fuel, and then continuing to bomb the south itself."
Israeli airstrikes killed at least 704 people over the past day, the Gaza Health Ministry said, mostly women and children. Hospitals were forced to close because of bomb damage and a lack of power amid the soaring death toll.
UN aid trucks could not cross into Gaza from Egypt on Tuesday as food, water, fuel and medicine supplies dwindled, following Israel's sealing off of the territory.
Israel said it had launched 400 airstrikes over the past day, killing Hamas commanders, hitting militants as they were preparing to launch rockets into Israel and striking command centers and a Hamas tunnel shaft. Israel reported 320 strikes the day before.
In Tel Aviv, five people were reportedly injured on Tuesday afternoon as Israelis ran for cover after sirens were heard.
Mr Guterres faced calls to resign from Israeli diplomats after telling the UN Security Council in New York: "It is important to also recognise the attacks by Hamas did not happen in a vacuum. The Palestinian people have been subjected to 56 years of suffocating occupation."
But he said the grievances of the Palestinian people cannot justify "the horrifying and unprecedented October 7 acts of terror" by Hamas in Israel, and demanded the immediate release of all hostages.
He also stressed that "those appalling attacks cannot justify the collective punishment of the Palestinian people".
His comments outraged the Israeli ambassador to the United Nations who called on Mr Guterres to resign "immediately" after the "shocking" speech.
Gilad Erdan wrote on X, formerly Twitter: "The shocking speech by the UN Secretary-General...while rockets are being fired at all of Israel, proved conclusively, beyond any doubt, the Secretary-General is completely disconnected from the reality in our region."His statement that 'the attacks by Hamas did not happen in a vacuum' expressed an understanding for terrorism and murder. It’s really unfathomable.He added: "The UN Secretary-General, who shows understanding for the campaign of mass murder of children, women, and the elderly, is not fit to lead the UN. I call on him to resign immediately. "There is no justification or point in talking to those who show compassion for the most terrible atrocities committed against the citizens of Israel and the Jewish people. There are simply no words."
Meanwhile Israel’s Minister of Foreign Affairs said he would not meet with Mr Guterres and said "there is no room for a balanced approach".
"Hamas must be erased from the world!" he wrote on X.
It comes as an elderly Israeli woman, the mother of a London-based artist and academic, told of how she was kept hostage by Hamas militants in a "spiders web" of underground tunnels.
Yocheved Lifschitz, 85, spoke to reporters on Tuesday after she was released by the militant group along with Nurit Cooper, 79, and reunited with her daughter Sharone Lifschitz.
Mrs Lifschitz said that the militants beat her with sticks, bruising her ribs and making it hard to breathe as they kidnapped her. They drove her into Gaza, then forced her to walk several kilometers (miles) on wet ground to reach a network of tunnels, she said.
During a press conference in London, families of people who continue to be held captive by Hamas said Mrs Lifschitz's release gives them “some hope” for their own loved ones.
Hamas and other militants in Gaza are believed to have taken roughly 220 people.
More than 5,700 Palestinians have been killed in the war, including the disputed toll from an explosion at a hospital last week, according to the Hamas-run health ministry.The fighting has killed more than 1,400 people in Israel, mostly during the initial Hamas attack on October 7, the Israeli government said.