"I fear that many more civilians will die," said Ajith Sunghay, head of the U.N. Human Rights Office for the Occupied Palestinian Territory.
"The continued attacks on specially protected facilities, such as hospitals, will kill civilians, and there will be a further, massive impact on access to health care, safety and security in general of Palestinians."
Israel's offensive has killed more than 26,000 Palestinians, according to Gaza health authorities, with thousands more feared buried under rubble and most of the 2.3 million residents displaced, facing acute shortages of food, water and medicine.
Israel launched its offensive in the wake of an Oct. 7 rampage by Hamas who killed 1,200 people and seized 240 hostages.
Sunghay said his office was also concerned about the impact of rainy and cold weather in Gaza.
"It was entirely predictable at this time of the year, and risks making an already unsanitary situation completely uninhabitable for the people," he said.
"Most have no warm clothes or blankets. Northern Gaza, where IDF (Israel Defence Forces) bombardment continues, is barely accessible, even to provide basic humanitarian aid."
Sunghay said it would be "disastrous" if the bombardment or the street-to-street fight taking place in Khan Younis moved further south to Rafah, where some 1.3 million people are now massed in the town bordering Egypt in an attempt to evade the Israeli assault.
