Rome - World leaders battled Wednesday to agree on how to tackle the global food crisis, making multi-billion dollar aid pledges but struggling to agree notably on biofuels, sources said.

    In a draft of the final declaration to be agreed Thursday, obtained by AFP, they vowed to use "all means" to ease suffering of those left hungry and poor by soaring food prices.

    But the draft, a final version of which is due to be agreed on Thursday, includes compromise language on the vexed issue of biofuels, which are promoted notably in the United States but criticized by others.

    In what critics would likely see as ducking the issue, they agreed that biofuels present both "challenges and opportunities" -- and say that more research is needed.

    "We are convinced that in-depth studies are needed to ensure the production and use of biofuels is sustainable ... taking into account the need to achieve and maintain food security," adds the draft, which was still being worked on.

    The wrangling over diplomatic language came after United Nations officials announced almost three billion dollars (2 billion euros) of new aid to help ease the food crisis, but UN chief Ban Ki-moon warned up to 20 billion dollars a year would be needed.

    "We simply cannot afford to fail," the UN Secretary General said at the food security summit in Rome, which is grappling with how to stop the crisis escalating. "Hundreds of millions of people expect no less."

    New funding totalling some 2.7 billion dollars was announced on the second day of the summit in Rome, where Ban has already demanded a 50 percent increase in food production by 2030.

    Food prices have doubled in three years, according to the World Bank, sparking riots in Egypt and Haiti and in many African nations. Brazil, Vietnam, India and Egypt have all imposed food export restrictions.

    John Holmes, head of the UN task force on the food crisis, said a "broad consensus" was building around an action plan, which is scheduled to be presented at a Group of Eight meeting in Japan later this month.

    World Bank President Robert Zoellick called for the lifting of trade barriers that contribute to food price inflation.

    "We need an international call to remove export bans and restrictions," he said. "These controls encourage hoarding, drive up prices and hurt the poorest people around the world who are struggling to feed themselves," he said.

    Humanitarian charity Oxfam spokesman Alexander Woollcombe said that criticizing developing countries' trade barriers distracted from the need for wealthy countries to re-examine their own trade policies.

    "Rich countries would do better to focus on fixing their own policies instead of criticizing developing country governments," he told AFP.

    World leaders also agreed that food security must be taken into account in a long hoped-for new world trade accord, according to the draft declaration.

    "We will strive to ensure that food agricultural trade and overall trade policies are conducive to fostering food security for all," they said, referring to last-gasp efforts to agree a World Trade Organization (WTO) deal.

    Former UN secretary general Kofi Annan put his signature Wednesday to a new initiative partnering the three UN food agencies with his Alliance for a Green Revolution in Africa (AGRA).

    "By unifying our efforts we can drastically step up our support for Africa's smallholder farmers," said Annan, stressing that the alliance would "focus on the small-scale farmer, not to run them out of business." Buyers pick maize at a market on the outskirts of Nairobi

    World Food Programme executive director Josette Sheeran announced the 1.2 billion dollars in new emergency aid. "With soaring food and fuel prices, hunger is on the march and we must act now," Sheeran said in a statement.

    The Islamic Development Bank would spend 1.5 billion dollars on agriculture in the poorest countries, FAO Director-General Jacques Diouf announced.