The Caribbean nation of 9 million people, the poorest in the western hemisphere, has a turbulent history of conflict, social turmoil, dictatorship, fragile institutions and devastating natural catastrophes. Many in the capital Port-au-Prince picked away at shattered buildings with bare hands, sticks and hammers hoping to find loved-ones alive. Thousands of homeless people began to set up their own camps anywhere they could, the biggest right opposite the collapsed presidential palace. "Look at us. Who is helping us? Right now, nobody," said Jean Malesta, a 19-year-old student who was the only survivor when her apartment building collapsed from the powerful quake that has killed thousands, possibly tens of thousands.

She and a dozen others lay under a tent they had set up in the park opposite President Rene Preval's palace. His weak and under-resourced government appears totally unequipped to handle the crisis, its officials in disarray and nowhere to be seen.

'WE ARE ON OUR OWN'

"So far, they have brought us nothing. We need water, food, shelter, everything, but we are on our own," Malesta added, to cries of agreement from women sitting and lying around her.

A major international aid effort has not yet kicked in, although plenty of small groups, many from the United States, have scrambled quickly, moving personnel into Haiti by plane and overland from neighboring Dominican Republic.

"The problem is that unlike traditional disaster situations we have few local partners to work with, because most of them have had their buildings destroyed and are looking for their own dead and missing," said Margaret Aguirre, a senior official with International Medical Corps.

Haitians are doing their best to survive chaotic conditions in the absence of any clear leadership, said Latin America expert Dan Erikson of the Washington-based Inter-American Dialogue think tank.

"The sad truth is that no one is in charge of Haiti today. This vacuum, coupled with the robust response from the Obama administration, has inevitably created a situation where the U.S. will be the de facto decision-maker in Haiti."

Even President Rene Preval lost his home. "My palace collapsed. ... I can't live in the palace, I can't live in my own house," he told CNN on Wednesday.

The 9,000-strong U.N. peacekeeping force, which might have been able to step into the void, has been left counting its own dead after its headquarters were destroyed in the quake.

The United Nations said 36 of its personnel in Haiti had been killed and many more were still missing.

Peacekeepers occasionally patrolled the city in buses and trucks and have mobilized some heavy earth-moving equipment but the blue-helmet soldiers have largely stayed off the streets.

Underlying the growing sense of chaos and abandonment around the half-destroyed coastal capital Port-au-Prince, some looting began -- a phenomenon Haitians have seen many times before in past political crises.

At one crushed supermarket, young men calmly carried off bags of food and electronics without a policemen in sight.

Pickup trucks stacked high with bodies could be seen making their way through traffic-clogged streets on Thursday morning, on their way to drop off the dead at the morgue attached to Hospital General, the city's main health facility.

But Guy LaRoche, the hospital's director, said it was already filled to overflowing with more than 1,500 rapidly decomposing bodies. Many had been left lying out in the sun. LaRoche said he had had no contact with any government officials to see what to do with them.

LOOMING HEALTH THREAT

"I'm awaiting the decision of the government. What else can I do?" he said. "The health threat, from disease, could be another catastrophe. We need nurses, medical teams, more of everything."

Around the city, many Haitians put rags and masks over their faces as the stench from rotting bodies began to rise. Crushed cars and vans stuck out of collapsed buildings, while children's toys, shoes and papers were scattered on streets.

In poor areas, there was little sign of any coordinated rescue activities.

"I think 50 percent of the city is destroyed," said Vladimir Rousseau, a 32-year-old diesel engineer, in the hard-hit Carrefour district.

Reuters witnesses saw some city blocks completely leveled, though in other areas the damage was more patchy.

In the upscale, hilltop Petionville sector, a Chilean contingent of U.N. peacekeepers -- many of whom arrived only last week and looked stunned at events -- were helping excavate rubble at the landmark Hotel Montana, which collapsed.

They said they had pulled out 14 people alive already, foreign customers and local workers alike, and thought there were dozens more underneath the stones.

"There is no one in our country capable of sorting this out. Everyone is looking after their own families. Only the world can come to our rescue," said shop owner Edner Baptiste.

Secretary of State Hillary Clinton, pledging U.S. help for Haiti's crippled government, said: "The authorities that existed before the earthquake are not able to fully function."

**Additional reporting by Carlos Barria, editing by Anthony Boadle, Pascal Fletcher and Will Dunham