The foreign ministers of 25 Western nations have slammed Israel for “drip feeding” aid into the Gaza Strip, as the health ministry in the territory said that more than 1,000 people have been killed seeking humanitarian relief there since late May.

The U.N. food agency accused Israel of using tanks, snipers and other weapons to fire on a crowd of Palestinians seeking food aid, in what the territory’s Health Ministry said was one of the deadlies...