Efforts to deliver medical supplies and fuel to Gazan hospitals have been increasingly constrained by hungry people stopping convoys in search of food, the World Health Organization said. “The safety of our staff and continuity of operations depends on more food arriving in all of Gaza, immediately,” Director General Tedros Adhanom Ghebreyesus said. Heavy bombardment and ground fighting continued across the Strip on Wednesday, the U.N. humanitarian affairs office said, including hostilities in the four long-standing refugee camps in central Gaza where Israeli forces had a day earlier warned they were expanding operations.