MILAN (AP) — Calling hunger "a terrible injustice," U.N. Secretary-General Ban Ki-moon marked World Food Day with a visit to the Milan Expo World's Fair, which is focusing on food security and nutrition.

Ban on Friday called for "food security for all the people around the world — to build a global movement to end hunger."

Italian officials presented him with the Milan Charter, signed by more than 1 million people during the six months of the fair, recording individual commitments to help secure food and water for the world's growing population.

The document hopes to boost one of the U.N.'s sustainable development goals, agreed upon by world leaders last month at the U.N. General Assembly, to eliminate hunger by 2030. It also aims to be an Expo 2015 legacy.