United Nations Secretary-General Antonio Guterres on Tuesday said what is happening in Gaza is horrendous and that the war in the Palestinian territory is morally, politically and legally intolerable.
Guterres also said he would be willing to meet with Israeli Prime Minster Benjamin Netanyahu and US President Donald Trump at the UN next week.
Israel unleashed a long-threatened ground assault on Gaza City on Tuesday, declaring "Gaza is burning" as Palestinians there described the most intense bombardment they had faced in two years of war.
An Israel military official said ground troops were moving deeper into the enclave's main city, and that the number of soldiers would rise in coming days to confront up to 3,000 Hamas combatants the army believes are still in the city.