(For full coverage, click on [nHAITI])
* U.S. helicopters land troops at presidential palace
* U.N. officials say humanitarian crisis under control
* Potentially fatal infections pose severe risk
* Haiti looks to long-term development assistance (Adds Zoellick, situation at epicenter, search for survivors)
By Tom Brown and Joseph Guyler Delva
PORT-AU-PRINCE, Jan 19 (Reuters) - U.S. Black Hawk helicopters swooped down on Haiti's wrecked presidential palace to deploy troops and supplies on Tuesday as a huge international relief operation to help earthquake survivors gained momentum.
The airborne troops in combat gear moved to secure Port-au-Prince's nearby General Hospital, where staff have been overwhelmed by patients seriously injured in the 7.0 magnitude that destroyed much of Haiti's capital one week ago.
Their arrival brought crowds of quake survivors camped out in the park opposite the palace rushing to its iron railings to gawk and beg for handouts of food.
It was one of the most visible and potentially sensitive deployments so far by the U.S. military, which is spearheading international efforts to assist millions of injured and homeless Haitians.
At least one Latin American leader, Venezuela's socialist President Hugo Chavez, a fiery critic of what he calls U.S. "imperialism," has already accused Washington of "occupying" Haiti under the pretext of an aid operation.
The commander of the U.S. troops in Haiti, Lieutenant General Ken Keen, said their primary purpose was humanitarian assistance and providing food and water to Haitians.
"Security goes hand-in-hand with our mission," he told CNN at the hospital protected by his men.
Watching the soldiers, quake survivor Gille Frantz said: "We know the world wants to help us, but it has been eight days now and I have not seen any food or water for my family."
Haitian officials say the death toll from the quake was likely to be between 100,000 and 200,000, and that 75,000 bodies had already been buried in mass graves.
In a bid to speed the arrival of aid and stem looting and violence, the U.N. Security Council unanimously agreed to temporarily add 2,000 U.N. troops and 1,500 police to the 9,000-member peacekeeping mission in Haiti. [ID:nN19217356]
Around 12,000 U.S. military personnel are on the ground, on ships offshore or en route. Haitian President Rene Preval has said U.S. troops will help U.N. peacekeepers keep order.
Soldiers spread out to other ravaged towns outside the capital -- to Leogane to the west and Jacmel on the southern coast -- to guard and supply aid distribution points there.
Troops were working to reopen the shattered seaport in Port-au-Prince so fuel and supplies could be brought in by ship. They also planned to open additional airbridges, using a runway at Jacmel and the San Isidro air base in the neighboring Dominican Republic.
Doctors Without Borders said its cargo plane with 12 tons of medical supplies had been turned away from the congested Port-au-Prince airport three times since Sunday and that five patients had died for lack of the supplies it carried. [ID:nN19100352]
"We were forced to buy a saw in the market to continue amputations," said Loris de Filippi, emergency coordinator for the group's Choscal Hospital in Cite Soleil.
Some 52 rescue teams from around the world raced against time to find people still alive under collapsed buildings. They have saved around 90 people, including an elderly woman pulled out on Tuesday from the rubble around the National Cathedral.
"I felt her grab my hand and squeeze. I felt as if God were squeezing my hand," said an emotional Javier Vazquez, the rescue crew member from Mexico who reached her.
Hours later as night fell, a dense plume of acrid smoke rose from a downtown street. Workers from Germany and Mexico, backed by sniffer dogs, continued sifting through the rubble of the church compound in hopes of unearthing more survivors.
"The overall security situation in Port-au-Prince remains stable, with limited, localized violence and looting occurring," the U.N. relief officials said in a statement.
Haiti's Police Chief Mario Andresol said his depleted force needs the help of U.N. peacekeepers because more than 4,000 criminals escaped from damaged prisons.
"It will be very difficult to get the bad guys back into jail," he said. "That is why we need outside help."
U.N. relief officials said the violence had not hampered distribution of food rations to 270,000 Haitians so far.
THREAT OF DISEASE
Medical teams pouring into Port-au-Prince to set up mobile hospitals warned of the immediate threats of tetanus and gangrene, as well as the spread of measles, meningitis and other infections in a nation where AIDS, tuberculosis, malaria and malnutrition were already rampant.
The World Health Organization said at least 13 hospitals were working in the Port-au-Prince area and it was bringing in medical supplies to treat 120,000 people over the next month.
"We are not past the emergency phase yet, but we are starting to look at the long term," said Margaret Aguirre of the International Medical Corps, whose staff had helped with 150 amputations so far.
In Leogane, the epicenter of the violent quake, the lack of facilities prevented many from getting live-saving surgeries. [ID:nN19234054]
"Even before all this drama, the hospitals here barely functioned," said Joel Beaubrun as he watched a U.S. military food drop. "You can imagine what it's like now."
International health experts stressed that the efforts in Haiti cannot stop once the immediate crisis is passed.
"This is about stepping to the plate for the long run," said Jon Andrus of the Pan American Health Organization.
Under the protection of U.S. troops, food and water and other emergency supplies have begun arriving more regularly at the U.S.-run airfield in Port-au-Prince.
The World Food Program said 270,000 people had received emergency food assistance by Monday night.
"We are looking at having 10 million ready-to-eat rations going out in the course of the coming week," WFP spokeswoman Emilia Casella said in Geneva. That would feed half a million people three times a day for a week.
Fuel prices have doubled and there were long queues outside gas stations, where cars, motorbikes and people with jerrycans lined up. Haitian police stood guard at some. [ID:nN19101861]
SOME SIGNS OF LIFE RETURNING
One sign of the return to normality was the emergence of street vendors selling fruit, vegetables and charcoal, although tens of thousands of survivors still clamored for help.
World leaders have promised massive assistance to rebuild Haiti and Preval appealed to donors to focus not just on immediate aid for Haitians but also on long-term development of the poorest nation in the Western Hemisphere.
Dominican President Leonel Fernandez proposed the creation of a $2 billion-a-year fund to finance Haiti's recovery over five years. [ID:nN18186669].
World Bank President Robert Zoellick told Reuters on Tuesday that while Haiti's level of development was among the lowest before the quake, the devastation gave the "opportunity to build back better." [ID:nN19108116]
"First and foremost that means that when the cameras leave, the donors don't leave with them," he said. (Additional reporting by Carlos Barria, Andrew Cawthorne, Catherine Bremer, Tom Brown in Port-au-Prince, Stephanie Nebehay in Geneva, Lesley Wroughton and Tabassum Zakaria in Washington; Writing by Anthony Boadle and Jane Sutton; Editing by Jackie Frank and John O'Callaghan)