PORT-AU-PRINCE - Secretary of State Hillary Clinton flew to Haiti on Saturday carrying relief supplies as the U.S. poured in massive aid four days after the earthquake that local officials say killed up to 200,000.

Haiti's shell-shocked government gave the United States control over its main airport to bring order to aid and food flights from around the world and speed up relief to the impoverished Caribbean nation.

Clinton left for Port-au-Prince on Saturday to meet with Haitian President Rene Preval at the airport. Her plane was to bring in supplies and return with evacuated Americans.

We will also be conveying very directly and personally to the Haitian people our long-term unwavering support, solidarity and sympathies, Clinton said.

Trucks piled with corpses have been carrying bodies to hurriedly excavated mass graves outside the city, but thousands of bodies still are believed buried under rubble.

U.S. rescuers worked through the night to dig out survivors from one collapsed supermarket where as many as 100 people could have been trapped inside. They were about to give up, when they were told a supermarket cashier had managed to call someone in Miami to say she was still alive inside.

We have already collected around 50,000 dead bodies, Interior Minister Paul Antoine Bien-Aime told Reuters. We anticipate there will be between 100,000 and 200,000 dead in total, although we will never know the exact number.

Some 40,000 bodies had been buried in mass graves, said Secretary of State for Public Safety Aramick Louis.

If the casualty figures turn out to be accurate, the 7.0 magnitude quake that hit Haiti on Tuesday and flattened much of its capital city would be one of the 10 deadliest ever.

Health Minister Alex Larsen told Reuters three-quarters of Port-au-Prince will have to be rebuilt.

Three days after the quake, gangs of robbers had begun preying on survivors living in makeshift camps on streets strewn with debris and decomposing bodies, as aftershocks rippled through the hilly neighborhoods.

Scores of police were on the streets of downtown Port-au-Prince on Saturday, rounding up looters in the biggest security presence since the earthquake struck, witnesses said.

Reuters photographer Carlos Barria saw police shooting in the air, grabbing and throwing people to the ground, and occasionally kicking detainees in parts of the city. But there was still no sign of widespread looting and riots many feared.

FIGHTING FOR FOOD

Hungry residents fought each other for bags of foods handed out by U.N. trucks in downtown Port-au-Prince.

A senior U.N. official warned that hunger will fuel trouble if aid does not arrive soon, although the law and order situation remains under control for the time being.

The United Nations mission responsible for security in Haiti lost at least 36 of its 9,000 members when its headquarters collapsed. Its two top officials have not been accounted for.

The weakened Haitian government was in no better position to handle the crisis. The quake destroyed the presidential palace and knocked out communications and power.

Preval and Prime Minister Jean-Max Bellerive were living and working in the judicial police headquarters.

I do not have a home, I do not have a telephone. This is my palace now, the president told Reuters in an interview.

We have to make sure there is gas available ... for the trucks collecting the bodies. The hospitals are full, they are overwhelmed.

The U.S. Navy hospital ship Comfort, a full service medical facility that can handle up to 1,000 patients, left the port of Baltimore on Saturday and was due in Haiti next week.

U.S. PROMISE

U.S. President Barack Obama, who pledged an initial $100 million in quake relief, promised the United States would do what it takes to save lives and get Haiti back on its feet. The scale of the devastation is extraordinary ... and the losses are heartbreaking, Obama said at the White House.

Obama said the United States, Brazil, Mexico, Canada, France, Colombia, Russia, Japan, Britain and other countries managed to fly in rescue and logistics personnel and supplies. While some aid was getting in, the White House hoped improved logistics would accelerate the effort.

Planes and ships arrived with rescue teams, search dogs, tents, water purification units, food, doctors and telecom teams, but faced a bottleneck at the small airport.

Air traffic control, hampered by damage to the airport's tower, now will be handled by the U.S. military with backup from a nuclear-powered aircraft carrier.

The USS Carl Vinson with 19 helicopters arrived off Haiti on Friday, opening a second significant channel to deliver help. Navy helicopters had begun taking water ashore and ferrying injured people to a field hospital near the airport.

The U.S. military aimed to have 9,000 to 10,000 troops on the ground in Haiti in ships offshore by Monday.

NO WATER, NO SUPPLIES

The Pan American Health Organization said at least eight hospitals and health centers in Port-au-Prince had collapsed or sustained damage and were unable to function.

We have no supplies. We need surgical gloves, antibiotics, antiseptic, disinfectant, said a doctor, Jean Dieudonne Occelien. We have nothing. Not even water. We have children out here with dry mouths and no water to give them.

At one collapsed supermarket, scores of people swarmed over the rubble to try to reach the food underneath. Just outside the Cite Soleil slum, desperate people crowded around a burst water pipe jostling to drink from the pipe or fill buckets.

Raggedly dressed survivors held out their arms to reporters touring the city, begging for food and water.

(Reporting by Joseph Guyler Delva and Eduardo Munoz in Port-au-Prince, Patrick Worsnip at the United Nations, Phil Stewart, Andrew Quinn and John Crawley in Washington; writing by Anthony Boadle and Patrick Markey; editing by Vicki Allen and Sandra Maler)

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