Parts of Gaza are officially experiencing a “man-made” famine, according to a Friday report by a United Nations-backed initiative, which added that the situation is expected to worsen after months of relentless conflict.

For an area to be experiencing famine, at least 30 percent of children under 5 must be considered acutely malnourished by height and weight measures. Using the arm circumference method, the I.P.C. said, the accepted threshold dropped to 15 percent.