United Nations peacekeepers warned yesterday that Haitis capital could quickly descend into rioting if three million hungry, thirsty and traumatised earthquake survivors dont receive emergency aid soon. The warning came as relief agencies battled to deliver tonnes of material to Haitis capital despite blocked roads, a clogged airport and shattered ports. Looters have emptied food shops and scuffles have broken out among survivors fighting over scarce water as the wait for help drags on. Brazils Defence Minister, Nelson Jobim, warned that the Brazilian-led peacekeeping force could struggle if desperation spilled into violence. We are worried about security, he said. As long as the people are hungry and thirsty, as long as we havent fixed the problem of shelter, we run the risk of riots. As the UN launched a flash appeal for $560 million (350 million), President Obama warned of difficult days ahead overcoming the logistical challenge of reaching the needy. Ban Ki Moon, the UN Secretary-General, said that food and water were in critically short supply as hundreds of thousands began their fourth night sleeping out in the open. Logistics are extremely difficult. The airport is open, but capacity is limited. A lack of transport and fuel is also hampering efforts. Many roads remain blocked, Mr Ban said. That said, the international communitys response has been generous and robust, and we are gearing up rapidly and effectively despite the challenging circumstances. As the 96-hour mark since the quake loomed, the UN called on countries to stop sending rescuers, a grim acknowledgement of the diminishing hope of finding survivors. The focus will now switch to getting in emergency supplies to keep those who have already been rescued alive. We dont need more disaster search-and-rescue teams, said Elisabeth Byrs, the UNs humanitarian spokeswoman said. That would only clog the airport. Last night the United States effectively took control of the vast relief operation as six naval vessels including an aircraft carrier to serve as a floating airport and 10,000 troops headed towards the country. Among the first distribution teams yesterday were US paratroopers who landed on Thursday night to help to secure the airport and lay the groundwork for the military mission. President Prval of Haiti sobbed with gratitude down the phone to Mr Obama, who reached him yesterday after three days of failed calls. He ended with a message to the American people, saying: From the bottom of my heart, and on behalf of the Haitian people, thank you, thank you, thank you. In a rare thaw in relations, Cuba agreed to allow US military aircraft into its airspace to evacuate the wounded to Miami. The concession shaves 90 minutes off the flight time from Guantnamo Bay, where casualties will receive initial treatment, to Miami where they can be taken to hospital. The only casualties to reach hospital in Miami yesterday, however, were 20 American citizens. In Port-au-Prince, Stefano Zannini, the head of mission for Mdecins sans Frontires, said his staff had been working around the clock under canvas to perform life-saving surgery on hundreds of people with dangerous open fractures. Thousands more were still awaiting help, and at least 100 had died before their wounds could be tended. People are still coming to our structures by any way they can, in cars, on motorbikes, even being carried on doors used as stretchers, he said. We have thousands ready for surgical interventions. With the citys tiny airport overwhelmed, aid organisations were struggling to find alternative routes to bring in vital medical supplies. Lorries bearing tarpaulins, high-energy food, water and medical supplies were beginning to reach the city by road yesterday after being flown into the Dominican Republic. With Port-au-Princes commercial docks destroyed by the quake, hopes of bringing sea cargo rest on the tiny northern port of Cap Hatien the only means by which to bring in the quantities of food required by hungry survivors. There was relief, however, at the discovery that a badly damaged UN food warehouse had not been looted as previously believed, allowing workers to retrieve 6,000 tons of food supplies to begin distributing at first light. (The Times)