World food production must rise by 50 percent by 2030 to meet increasing demand, U.N. chief Ban Ki-moon told world leaders Tuesday at a summit grappling with hunger and civil unrest caused by food price hikes.

The secretary-general told the Rome gathering that nations must minimize export restrictions and import tariffs during the food price crisis and quickly resolve world trade talks.

"The world needs to produce more food," Ban said.

The Rome-based U.N. Food and Agriculture Organization is hosting the three-day summit to try to solve the short-term emergency of increased hunger caused by soaring prices and to help poor countries grow enough food to feed their own.

In a message read to the delegates, Pope Benedict XVI said "hunger and malnutrition are unacceptable in a world which, in reality, has sufficient production levels, the resources, and the know-how to put an end to these tragedies and their consequences."

The increasing diversion of food and animal feed to produce biofuel, and sharply higher fuel costs have also helped to shoot prices upward, experts say.

The United Nations is encouraging summit participants to start undoing a decades-long legacy of agricultural and trade policies that many blame for the failure of small farmers in poor countries to feed their own people.

Wealthy nations' subsidizing their own farmers makes it harder for small farmers in poor countries to compete in global markets, critics of such subsidies say. Jim Butler, the FAO's deputy director-general, said in an interview ahead of the gathering that a draft document that could be the basis for a final summit declaration doesn't promise to overhaul subsidy policy.

Congress last month passed a five-year farm bill heavy on subsidies, bucking White House objections that such aid in the middle of a global food crisis wasn't warranted.

The head of the summit's U.S. delegation, Agriculture Secretary Ed Schafer, insisted on Monday that biofuels will contribute only 2 or 3 percent to a predicted 43 percent rise in prices this year.