WASHINGTON — President Barack Obama on Friday said the United States has a “moral imperative” to lead the fight against hunger and malnutrition in Africa despite shrinking national budgets around the world.

Pres. Obama announced $3 billion in private sector pledges to help boost agriculture and food production in Africa. He said the U.S. and other donor nations would continue to make “historic investments” in development, though he offered no new American government pledges.