PORT-AU-PRINCE, Haiti  As tension rose here in the battered Haitian capital, relief workers scrambled on Friday to deliver desperately needed food, water and medical care, recover survivors still trapped in the rubble and collect thousands of decaying bodies from the streets. 
 
 An immense relief operation was under way, with cargo planes and military helicopters buzzing over the crowded Toussaint Louverture International Airport. But three days after the earthquake struck, with many cries for help going silent, not nearly enough search and rescue teams or emergency supplies could make it here. The United Nations said it had fed 8,000 people, while two million to three million people remained in dire need. 
 
 Patience was wearing thin, and reports of looting increased, as another day went by with no power and limited fresh water. 
 
 “For the moment, this is anarchy,” said Adolphe Reynald, a top aide to the mayor of Port-au-Prince, as he supervised a makeshift first aid center that was registering long lines of wounded people but had no medicine to treat them. “There’s nothing we can do. We’re out here to show that we care, that we’re suffering along with them.” 
 
 The United Nations said that 9,000 people had been buried in mass graves  and collecting bodies had become one of the few ways to earn money. 
 
 “They pay me $100 a day,” Valencia Joseph, 32, said Friday at 2 a.m., as he was called to tug a body free of wires. “We must have picked up 2,000 bodies.” 
 
 He added, “And there’s more.” 
 
 In Washington, Secretary of State Hillary Rodham Clinton said she would visit Haiti on Saturday to show support for the victims of the 7.0-magnitude quake. The Obama administration, cautioning that it would take time for all the aid to reach those in need, granted Haitians living in the United States protection from deportation for 18 months and permission to work. 
 
 Mr. Obama said he had spoken with the Haitian president, René Préval, and pledged the United States’ full commitment in helping rebuild from a quake that, according to United Nations estimates, destroyed at least 30 percent of the capital and half the buildings in some neighborhoods. 
 
 “As I told the president, we realize that he needs more help and his country needs more help  much more,” Mr. Obama said. “And in this difficult hour, we will continue to provide it.” 
 
 The United States, in fact, took firmer control of the emergency operation on Friday. After three days of chaos and congestion at the airport in Port-au-Prince, Haiti’s government ceded control of it to American technicians, to speed the flow of relief supplies and personnel. 
 
 The Federal Aviation Administration, which began managing air traffic into Haitian airspace, issued a stern warning to allow aid to flow in a more orderly way: no planes from the United States, military or civilian, would be allowed to land without express permission from the agency. 
 
 Exceptions to the new rule would be granted only to humanitarian aid planes, based on arrival times and on the availability of space at the airport, a notice from the agency said. The F.A.A. warned pilots that fuel still was not available at the airport, and that any aircraft bound here would need to have enough fuel to circle in the air for at least an hour. 
 
 Adm. Mike Mullen, the chairman of the Joint Chiefs of Staff, said that 9,000 to 10,000 American troops were expected in Haiti, on shore and off, by Monday, and that the Pentagon was poised to send more. 
 
 Speaking at a Pentagon news conference, Admiral Mullen said that about 5,000 would be ground troops, who would help with security and logistical support, among other duties; the rest would be on ships. He said that an American aircraft carrier, the Carl Vinson, arrived off Haiti early Friday with 19 helicopters aboard, and that it would serve as a staging area for relief flights, purified water and other supplies. 
 
 Port-au-Prince, volatile in normal times, remained relatively calm, but the United Nations reported that one of its food warehouses in the capital had been looted. It called the theft limited and said it had recovered most of its provisions. 
 
 Looting of houses and shops increased Friday, and anger boiled over in unpredictable ways: residents near the city’s overfilled main cemetery stoned a group of ambulance workers seeking to drop off more bodies. 
 
 Some people were bracing for the worst. Harold Marzouka, a Haitian-American businessman who was hustling his family onto a private jet to Miami, said he could feel the tension rising and feared that hunger and desperation might prompt an explosion of violence. 
 
 “If aid doesn’t start pouring in at a significant level, there will be serious consequences on the streets,” he said. “People are in the shocked and frightened phase. But the next phase will be survival.” 
 
 In New York, the United Nations secretary general, Ban Ki-moon, said he recognized that the slow pace of the relief effort could make people in Port-au-Prince restive. ||||| Up to 100,000 people may have died in the Haiti earthquake, the Pan American Health Organisation has said, as the UN launches an appeal for more than $550m (£337m) in aid. 
 
 "A variety of sources are estimating the numbers [at] between 50,000 and 100,000," said Jon Andrus of PAHO, the Americas arm of the World Health Organisation. 
 
 Barack Obama said the US would do everything it could to get the country back on its feet. "The scale of the devastation is extraordinary ... and the losses are heartbreaking," he said at the White House. 
 
 In Britain, the Disasters Emergency Committee has launched an appeal for aid. The British Red Cross said £1m was raised in the first 36 hours of its appeal. 
 
 Initial estimates spoke of 45,000 to 50,000 deaths, and the sharp rise comes as peacekeepers in Haiti warn that security has become an urgent priority amid fears of a breakdown in order. 
 
 UN troops patrolling the capital said there was rising anger that aid had not been distributed quickly. The Brazilian military advised that aid convoys should add security to guard against looting. 
 
 "Unfortunately they're slowly getting more angry and impatient," said David Wimhurst, spokesman for the Brazilian-led UN peacekeeping mission. 
 
 "I fear … we're all aware that the situation is getting more tense as the poorest people who need so much are waiting for deliveries. I think tempers might be frayed." 
 
 Fevil Dubien, an aid worker, said some people were almost fighting over the water that he handed out from a truck in a northern Port-au-Prince neighbourhood. 
 
 Security was the biggest problem, Delfin Antonio Rodriguez, the rescue commander from the neighbouring Dominican Republic, told the AFP news agency. "Yesterday they tried to hijack some of our trucks. Today we were barely able to work in some places because of that." 
 
 The UN World Food Programme partly retracted a statement that looters had raided one of its warehouses containing 15,000 tonnes of food aid. In the new statement it said 6,000 tonnes of food remained in the building. A spokesperson said looting was not unusual in disaster situations when people were without the most basic supplies such as water. 
 
 The UN said it would launch a flash appeal this afternoon in New York for $550m in aid. A flash appeal is a way of structuring a co-ordinated humanitarian response. The former US president Bill Clinton said he would try to model a disaster assistance fund along the same lines he and former president George Bush Sr pursued for victims of the Asian tsunami. Barack Obama has asked Clinton, a UN special envoy to Haiti, to work with George Bush, the previous president, on a fundraising effort. 
 
 Hundreds of US troops and an aircraft carrier arrived in Port-au-Prince, raising hope that the situation would improve in the coming hours. 
 
 "We have much more support on the way," said the US commander in the capital, Lieutenant General Ken Keen. "Our priority is getting relief out to the needy people, to mitigate the suffering that the Haitian people are experiencing right now." 
 
 The US aircraft carrier Carl Vinson arrived off Haiti's shores overnight with 19 helicopters. It started flights from its deck this morning. 
 
 The carrier has water purifying equipment and three surgical operating rooms, and can do medical evacuations as well as ferrying supplies and people to and from land. 
 
 The arrivals added to more than 300 military personnel who had already landed in Haiti. 
 
 The 82nd Airborne was sending another 800 troops and aiming for a full brigade of 3,500 on the ground by the end of the weekend. 
 
 Jan Egerland, a former UN humanitarian chief, said he expected the arrival of aid to speed up. "We are in a very classic development. Days three, four and five are the most frustrating. Everybody knows that the whole world is mobilising and everyone has heard the promises. But it takes time to reach the beneficiaries. The infrastructure has either gone or totally clogged up," he told the BBC. 
 
 He said the inability of the Haitian government to direct relief operations and the death of the head of the UN mission in the country meant the US was effectively in charge of the situation. 
 
 The small airport in Port-au-Prince has struggled to cope with the stream of aid flights. Some have been turned away and little of the aid that has landed has arrived in the most needy areas. 
 
 Bodies lay all around the hilly city, with people covering their mouths and noses with cloth to block out the smell. Corpses were piled on pickup trucks and delivered to the general hospital in Port-au-Prince, where the hospital director, Guy LaRoche, estimated there were 1,500 bodies piled outside the morgue. 
 
 More than 48 hours after the 7.0 magnitude earthquake struck, people clamoured for food and water and continued digging for relatives missing under the rubble. "We need food. The people are suffering. My neighbours and friends are suffering," said Sylvain Angerlotte, 22. "We don't have money. We don't have nothing to eat. We need pure water." 
 
 Aid workers warned that time was running out for the thousands still trapped in the rubble. One described his frustration at hearing the cries of trapped people but being unable to help them because of a lack of heavy machinery. 
 
 Rezene Tesfamariam, the Haiti director of charity Plan International, said people were using their bare hands or basic tools such as shovels and pick-axes to dig for their loved ones. 
 
 "There are people still alive underneath [rubble], you can hear them crying for help, but time is running out. It is beyond the means of individuals to reach them. They are trying to move concrete with their hands. What is desperately needed is proper machinery and equipment to lift the rubble." 
 
 Tesfamariam said vehicles and equipment were urgently needed to remove the tens of thousands of bodies. 
 
 "I have been travelling round the city to find where we can provide assistance and I see dead bodies lying in the street everywhere."
– Earthquake survivors desperate for food broke into a UN warehouse in Port-au-Prince today, a sign of the growing frustration at delays in relief. UN officials say they've recovered nearly all of their stocks, however, and pledged to hand out 6,000 tons of food shortly. But with necessities such as water, medical supplies, and heavy moving equipment slow to arrive, anger and despair are rising among the tens of thousands of survivors in the capital. "We're all aware that the situation is getting more tense as the poorest people who need so much are waiting for deliveries," a Brazilian peacekeeper tells the Guardian. "They are slowly getting more angry," a UN official tell the New York Times. In other developments: Cuba gave the US permission to use its airspace for relief flights. About 4,000 inmates who escaped from the main prison remain at large. About 7,000 bodies have been buried so far in a mass grave. Two big aftershocks rattled the capital again today.