“We are gravely concerned about the continued bombardment of Middle Gaza by Israeli forces, which has claimed more than 100 Palestinian lives since Christmas Eve,” said U.N. Human Rights Office spokesperson Seif Magango.

“Israeli forces must take all measures available to protect civilians. Warnings and evacuation orders do not absolve them of the full range of their international humanitarian law obligations.”

Israel is determined to destroy Hamas despite global calls for a ceasefire in the 11-week-old war and new concerns the conflict could spread with U.S. and Iran-aligned forces attacking each other elsewhere in the region.

Since Hamas killed 1,200 people and captured 240 hostages on Oct. 7 in the deadliest day in Israeli history, Israeli Prime Minister Benjamin Netanyahu has responded with an assault that has laid much of Hamas-ruled Gaza to waste.

Palestinian health authorities said nearly 21,000 people had been killed in Israeli strikes, with thousands more feared buried under rubble. Nearly all of the enclave’s 2.3 million people have been driven from their homes, many several times.

Israel says it is doing what it can to protect civilians, and blames Hamas for putting them in harm’s way by operating among them, which Hamas denies. But even Israel’s closest ally the United States has said it should do more to reduce civilian deaths from what President Joe Biden has called “indiscriminate bombing”.