The United Nations on Friday issued a flash appeal of US$550 million to provide emergency care to thousands of Haitians suffering from the fallout of Tuesday's earthquake that has devastated the country and created an epic humanitarian challenge.

"The situation has been quite dramatic," UN chief Ban Ki-moon told reporters, adding that roughly 3 million people in the nation's capital, Port-au-Prince, need tents, water and food.

The outpouring of support so far from the international community has been "generous and robust," said Ban, but he admitted that logistics and the lack of coordination have made delivering aid extremely difficult.

"There is clearly some lack of coordination," he said. "Roads are still not all opened and there are some problems in delivering assistance materials but as time goes by I'm sure we will be more coordinated."

Ban said he would travel to Haiti "very soon" but did not give a date and did not indicate whether former US President and special UN envoy to Haiti Bill Clinton would accompany him.

During the course of Thursday night, eight flights of humanitarian cargo arrived, said Ban, but clearly the airport in Port-au-Prince is has reached its capacity. Media reports from Haiti paint a picture where planes can arrive but cannot leave because of a lack of fuel. Roads remain blocked because of collapsed buildings and heavily lifting equipment is scant.

"The situation is more difficult than any of us would wish," he said. "We are mobilizing all resources as fast as we can."

Preliminary estimates show widespread damage to infrastructure with as much as up to 50 percent of the buildings in the capital and other areas hit by the strong earthquake were damaged or destroyed. Later, John Holmes, the UN under-secretary-general for humanitarian affairs, said that 30 percent of the capital's infrastructure has been destroyed.

The 7.0-magnitude quake hit especially close to the United Nations family as it appears more staff were killed in one day than during any other incident.

UN spokesperson Martin Nesirky said the death toll for United Nations staff has climbed to 37, with 36 people from the UN peacekeeping force, MINUSTAH, and one person from the World Food Program (WFP).

The WFP confirmed that one of their staff had deceased but declined to give details.

Out of a total of 12,000 UN national and international staff, 330 are missing or unaccounted for, said Nesirky, who added that many could be safe but because of failed communication lines, have been unable to relay information on their whereabouts.

Meanwhile, the security situation on the ground appears to be growing more tense by the day, with UN officials warning that if victims of the quake do not receive food and water soon, tensions will begin to fray.

Already, there are reports of widespread looting. Ban noted that he was "very much concerned" about deteriorating security but said that the UN peacekeeping force, of which there are 3,000 in Port-au-Prince, was working closely with the National Haitian Police (HNP).

This contradicted earlier reports from UN peacekeeping force spokesperson David Wimhurst who told reporters in New York via video conference that the HNP had "simply vanished."

Wimhurst warned that with limited assistance, many Haitians are beginning to get "angry and impatient."

On Thursday, the WFP began distributing food to 8,000 people several times a day, said Ban, noting it is "only a drop in the bucket."

Within 15 days the UN food agency hopes to feed one million people and within one month that figure is expected to climb to 2 million.

(Xinhua News Agency January 16, 2009)