DEIR AL-BALAH, Gaza Strip — Malnutrition rates among children in the Gaza Strip have doubled since Israel imposed sharp restrictions on the entry of food in March, the U.N. said Tuesday. New Israeli strikes killed more than 90 Palestinians, including dozens of women and children, according to health officials.

Israel’s air and ground war has destroyed vast areas of Gaza and driven some 90% of the population from their homes. Aid groups say they have struggled to bring in food and other assistance because of Israeli military restrictions and the breakdown of law and order, and experts have warned of famine.