ROME — Delegates in the closing hours of a three-day U.N. summit were trying to agree Thursday on a final document on how to tackle growing hunger and civil unrest sparked by skyrocketing prices of food and fuel.

But Cuba and some other Latin American countries were insisting on language condemning embargoes, and Argentina was objecting to calls in the document to ease trade restrictions, participants and U.N. officials said.

The protracted wrangling forced U.N. Food and Agriculture Organization officials to put off a planned news conference from late afternoon to early evening.

The embargo snag figured in the failure of a late-night round of talks Wednesday to reach agreement, said Nick Parsons, a spokesman for the Rome-based FAO, which hosted the summit.

The United States, a huge aid donor, opposes efforts to condemn its long-running embargo against communist-run Cuba.

"Our policy on Cuba hasn't changed," U.S. Agriculture Secretary Ed Schafer told reporters as negotiators worked behind closed doors to try to salvage an accord. He headed the U.S. delegation, which declined to comment on the embargo demand.

U.N. Secretary-General Ban Ki-moon had told the summit such trade measures as import taxes and export restrictions must be minimized to help ease world hunger caused by soaring food prices.

The Argentines were dissatisfied with the draft's wording calling for a "reduction in trade barriers," Guatemalan Agriculture Minister Raul Robles said.

Export taxes have been a hot political issue in Argentina, where farmers have resorted to strikes to protest a tax hike on soy and sunflower seed exports.

The government says the higher revenue is needed to redistribute the wealth to the poor, but farmers say the hikes make it difficult to earn a living.

The Argentine delegation did not immediately return calls requesting comment.

Robles said discussions with Havana's representatives indicated the embargo snag was approaching a solution.

Parsons said another sticking point in the talks going into Thursday involved some French reservations over language calling for world trade talk progress.

A final draft of the summit declaration that was being haggled over Thursday calls for stepped up food production, reduced trade restrictions and more research on the contentious issue of biofuels.

A copy of the draft obtained by The Associated Press ends with a pledge to alleviate the suffering caused by the crisis, to stimulate food production, to increase investment in agriculture, to address obstacles to food access and to use the planet's resources in a sustainable way.

The declaration of resolve to "address obstacles to food access" could be taken to refer to, among other restrictive measures, embargoes.

Previous food summits in Rome dating back to the last decade have also seen Cuba press for condemnation of the embargo.

The draft sought a balance between contrasting positions on biofuels that were highlighted during the summit. It said it was "essential" to address the "challenges and opportunities" posed by biofuels.

"In-depth studies are necessary to ensure that production and use of biofuels is sustainable," it said.

Fuels made from sugar cane, corn and other crops have been seen as a way to combat climate change and rising oil prices. The United States has been heavily subsidizing corn-based ethanol production. Last year, the 27-nation European Union endorsed a plan calling for biofuels to make up 10 percent of the fuel for road vehicles by 2020.

But environmentalists, international groups and some countries are becoming increasingly wary of biofuels, which they say could accelerate global warming by encouraging deforestation — and contribute heavily to the commodities price hike by diverting production from food crops to biofuel crops.

The draft calls on the international community to continue efforts "in liberalizing international trade in agriculture by reducing trade barriers and market-distorting policies."

The document also echoes Ban's call to increase food production by 50 percent by 2030 to meet rising demand.

Ban predicted that as much as $20 billion may be needed each year to increase food production.