Rome ? World leaders at a U.N. summit pledged Thursday to reduce trade barriers and boost agricultural production to combat a food crisis that is spreading hunger and violent unrest across the world.

After three days of wrangling, delegates from about 180 countries approved a declaration resolving to ease the suffering caused by soaring food prices and step up investment in agriculture.

The summit also struck a balance on the contentious issue of biofuels, recognizing that there are both “challenges and opportunities” in using food for fuel.

A few Latin American countries raised strong objections to parts of the declaration.

Cuba was disappointed the document didn’t criticize the long-standing U.S. embargo against the Communist-ruled island. Argentina was unhappy it didn’t blame farm subsidies in the U.S., European Union and other Western food-producers for a major role in driving up prices.

The declaration called for swift help for farmers in poor countries who need seed and fertilizers in time for the approaching planting season.

“We took the measure of the problem of hunger in the world correctly,” said Jacques Diouf, head of the Rome-based U.N. Food and Agriculture Organization, which hosted the summit.

“I think we have an essentially political declaration” of intent to ease hunger, Diouf said.

But it remains to be seen if the words adopted in Rome will translate into changed farm or trade policies at home.

Diouf said that although the gathering wasn’t a conference for pledging donations, billions of dollars from countries, regional banks and the World Bank had been promised in recent days.

U.N. Secretary-General Ban Ki-moon had told the summit such measures as import taxes and export restrictions must be minimized to alleviate hunger, and the document called for “reducing trade barriers and market-distorting policies.”

U.S. Agriculture Secretary Ed Schafer welcomed the declaration on biofuels, saying the United States remains “firmly committed to the sustainable production and use of biofuels, both domestically and globally.”