A strong aftershock struck Haiti on Wednesday, creating panic among people camping out in the capital's streets after last week's devastating earthquake.
The 6.1 aftershock rattled already shattered buildings but there were no immediate reports of damage from the tremor, which struck after daybreak. Fearing damage from aftershocks, thousands of people have been sleeping in streets in the capital Port-au-Prince since the Jan. 12 earthquake.
The US Geological Survey said Wednesday's tremor was centered 26 miles (42 km) west-northwest of Jacmel.
Fears of violence and looting have eased in Haiti as US troops provided security for water and food aid deliveries, and thousands of displaced Haitians heeded the government's advice to seek shelter outside Port-au-Prince.
Medical care, handling of corpses, shelter, water, food and sanitation remain the priorities for the international operations, UN relief officials said a week after the magnitude 7 quake.
While military escorts still are needed to deliver relief supplies, the United Nations said security problems were mainly in areas considered "high risk" before the Jan. 12 quake. Some 4,000 criminals escaped from damaged prisons soon after the temblor hit.
"The overall security situation in Port-au-Prince remains stable, with limited, localized violence and looting occurring," the UN Office for Coordination of Humanitarian Affairs said.
US Black Hawk helicopters swooped down on the grounds of Haiti's wrecked presidential palace on Tuesday, deploying troops and supplies and immediately attracting crowds of survivors who clamored for handouts of food.
Around 12,000 US military personnel are on the ground in Haiti, on ships offshore or en route, including the USNS Comfort hospital ship, which was to arrive in the area on Wednesday, providing essential capacity for complex surgeries.
At least one Latin American leader, Venezuela's socialist President Hugo Chavez, a fiery critic of what he calls US "imperialism," already has accused Washington of "occupying" Haiti under the pretext of an aid operation.
But Haitian President Rene Preval has said US troops will help UN peacekeepers keep order.
In a bid to speed the arrival of aid and stem looting and violence, the UN Security Council this week unanimously agreed to temporarily add 2,000 UN troops and 1,500 police to the 9,000-member peacekeeping mission in Haiti.
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."
The World Food Program, which has fed 200,000 quake victims, aims to move the equivalent of 10 million ready-to-eat meals in the next week, the United Nations said. An additional 130,000 have been fed by other relief groups.
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.
In Leogane, the epicenter of the violent quake, the lack of advanced medical facilities prevented many severely injured from getting life-saving surgeries.
"Even before all this drama the hospitals here barely functioned," said Joel Beaubrun as he watched a US military food drop. "You can imagine what it's like now."
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 five patients died for lack of the supplies it carried.
"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.
Doctors Without Borders said in a statement: "Drugs for surgical care and equipment like dialysis machines are urgently needed but access problems for cargo shipments are causing delays in delivery."
It quoted Paul McMaster, a surgeon at Carrefour hospital, as saying: "We've run out of plaster of Paris for fractures and we've no crepe bandages at the moment. So it's just a nightmare to get these basic materials."
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.
So far, feared infectious diseases have not shown up, although many injured faced the immediate threats of tetanus and gangrene, and hospitals were overwhelmed.
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.
Some 90 people have been pulled from the rubble by the 52 rescue teams from around the world, and untold numbers of others by Haitians digging through collapsed buildings. Racing against time, they hoped for a repeat miracle like that of 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.
SOME SIGNS OF NORMALITY
UN relief officials said thousands of survivors were heeding the government's plea that they move to friends and family in safer areas outside the earthquake zone. Royal Caribbean Cruises has resumed its stops at its private beach on the north coast of Labadee.
One sign of the return to normality was the emergence of street vendors selling fruit, vegetables and charcoal, though tens of thousands of survivors still clamored for help and supplies of staples were scarce and costly.
Although damaged local banks were not reopening yet, the United Nations said there were plans for them to open 30 to 40 distribution points so people could access accounts.
Fuel prices have doubled, and there were long lines of cars, motorbikes and people with jerrycans outside gas stations. Haitian police stood guard at some.
The World Food Program was planning to bring in 10,000 gallons (40,000 litres) of diesel a day from neighboring Dominican Republic.
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 Dominican Republic.
Citing Haiti's water shortages, US Agency for International Development head Rajiv Shah told reporters world aid needed to focus on longer term development. "I think 70,000 bottles have already been distributed, of outside water, but the main effort is about creating sustainable local production," he said at the White House.
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.
World Bank President Robert Zoellick said on Tuesday the devastation gave the "opportunity to build back better."
Experiences in countries hit by war and disasters also showed that aid should be in the form of grants and not loans, and should be pooled in a multi-donor trust fund managed by the World Bank, he said.