Bush took action a day after top finance and development officials from around the world called for urgent steps to stem rising food prices, warning that social unrest would spread unless the cost of basic staples was contained.

"This additional food aid will address the impact of rising commodity prices on U.S. emergency food aid programs and be used to meet unanticipated food aid needs in Africa and elsewhere," the White House said in a statement.

Bush directed the agriculture secretary to draw down on the Bill Emerson Humanitarian Trust, a food reserve for emergency needs in the developing world, to free up about $200 million through the U.S. Agency for International Development.

White House spokeswoman Dana Perino had said Bush, who was briefed about the food crisis during a cabinet meeting earlier on Monday, was "very concerned" and asked senior aides to look into ways the United States could help ease shortages.

Washington provided more than $2.1 billion in international food aid in fiscal 2007.

Perino had said the administration was sticking to its proposal to buy more of the food used in assistance programs from suppliers closer to needy countries, which would cut transportation costs. U.S. agricultural interests have resisted the idea.

APPEAL FOR ACTION

The White House announcement followed a weekend meeting of the International Monetary Fund and World Bank's Development Committee in Washington where attendees called for the rising food prices to be addressed at the highest political levels.

World Bank President Robert Zoellick on Sunday cited the World Food Program's appeal to developed countries for $500 million by May 1, saying it had received commitments for almost half of that, but that it was not enough.

Concerns about food costs took on new urgency as senators in Haiti ousted the prime minister after a week of food-related rioting in which at least five people died. There also have been protests in Cameroon, Niger and Burkina Faso in Africa, and in Indonesia and the Philippines.

At the United Nations on Monday, Secretary-General Ban Ki-moon said rapidly worsening food shortages around the world had "reached emergency proportions."

"We need not only short-term emergency measures to meet urgent critical needs and avert starvation in many regions across the world but also a significant increase in long-term productivity in food grain production," Ban said.

"The international community will also need to take urgent and concerted action in order to avert the larger political and security implications of this growing crisis," he told a meeting of the U.N. Economic and Social Council with international financial and trade bodies.