They cried loudly, twisting as if in pain, not from disease but from the hunger gnawing away at them. Here, U.N. officials’ increasingly dire warnings that a hunger crisis is growing around the world are becoming reality. U.N. agencies have warned that some 250 million people in 20 countries are threatened with sharply spiking malnutrition or even famine in coming months. The United Nations humanitarian office this week released $100 million in emergency funding to seven countries most at risk of famine — Yemen, Afghanistan, South Sudan, Ethiopia, Nigeria, Congo, and Burkina Faso. But David Beasley, head of the World Food Program, says billions in new aid are needed.