WASHINGTON, May 6 (Reuters) - The World Food Program, facing an unprecedented surge in the price of food it provides to the world's hungry, has secured about 60 percent of the extra funds it needs to cover planned aid donations this year, the head of the United Nations agency said on Tuesday.

"We put out an extra appeal for $755 million and we're about 60 percent of the way there," WFP Executive Director Josette Sheeran said during a speech at a Washington think tank.

Donor nations like Canada, Australia and Britain have stepped up their pledges to help WFP, which aims to help feed the estimated 850 million undernourished people around the world, cope with soaring costs of basic foodstuffs.

Global food prices -- including staples like rice, wheat and corn -- soared an annual 43 percent through March, according to the U.S. government.

The United States, the world's largest donor of food aid, last month released 260,000 tonnes of wheat from an emergency crop trust.

Last week, President George W. Bush announced plans, which must be approved by Congress, to spend an additional $770 million on food aid and agriculture development in the fiscal year beginning Oct. 1.