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KANSAS CITY, Mo., April 15 (Reuters) - The United Nations' World Food Program has seen a startling increase in the cost of providing global food aid even since it made an emergency appeal for an extra $500 million in February, the organization's executive director said on Tuesday.

Josette Sheeran, who heads the Rome-based U.N. agency, said commodity and fuel costs had risen "even more dramatically" since it made its appeal.

The price WFP pays for rice, a staple in many poor countries, jumped from around $460 a tonne in the beginning of March to $780 a tonne now, Sheeran told a U.S. government conference on food aid.

Donor countries and aid groups are struggling to stretch budgets to match soaring food prices, which have taken off in the past few years as new investment money pours into commodity markets and biofuel production consumes more of the world farm output.

Global food prices increased close to 40 percent in 2007, and prices are expected to remain high for at least two to three years.

High prices have triggered riots and violence in a host of poor and developing countries, especially those which rely on imports for the bulk of food supplies. (Reporting by Missy Ryan, editing by Matthew Lewis)

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