PORT-AU-PRINCE, Haiti—Emergency aid flowed from around the world toward Haiti on Thursday, only to confront a reality that grew more desperate by the hour: Crippled ports and communications left stunned earthquake survivors on their own to scavenge for food and water, carry away legions of dead and dig frantically for voices calling out from under the rubble.
President Obama promised $100 million and the full resources of the U.S. government for what he said would be one of the largest relief efforts in recent history. U.S. officials said 30 countries had either sent aid or promised to do so. Rescue teams from eight countries already had arrived.
"In Haiti, you're lucky if they come with a screwdriver," said Jean Marc Mercier, a Haitian American who spent the last two days hunting for survivors in the wreckage of the Hotel Montana, a longtime gathering spot for diplomats, journalists, humanitarian workers and businessmen.
The toppled six-story hotel was an exception to the scenes of abandonment elsewhere; a rescue team newly arrived from Virginia was combing the debris.
Mercier, who runs a computer business in Haiti, said he and others had been burrowing by hand toward voices calling out from deep inside the wreckage. They had managed to save one woman, an aid worker.
"Last night after I went to bed, all I heard were the voices in my head. One guy told me not to bother: 'Go help people who are in better shape. There is no way you are getting to me,' " said Mercier, 44. "I wasn't able to sleep all night."
Asked how many people were in the hotel when it collapsed, he whispered, "Hundreds."
Aid officials said the risk of violence and looting would increase as scant food and water run out and frustrated families fail to find medical care for the injured.
Officials who were willing to estimate the number of dead acknowledged that they were just guessing. Victor Jackson, an official with Haiti's Red Cross, told Reuters news agency that his organization was estimating 45,000 to 50,000 had died.
All across Port-au-Prince, it seemed, the living bore the dead -- in the beds of pickups, in wheelbarrows, on makeshift stretchers. At a hospital named St. Marie, crowded a day earlier with dozens of people seeking help, the courtyard was empty except for two cleaners mopping bloody water into the street.
Even many who didn't lose their homes were afraid to sleep in them.
Lionel Aceveje, a police officer who lives in a hillside shantytown near the suburb of Petionville, said his family of six was sleeping outside in the evening chill. "Every little shaking terrifies us," he said.
Both the air- and seaports were proving to be bottlenecks for the international aid effort.
Dr. Paul Farmer, a Harvard medical professor and U.N. deputy special envoy to Haiti, said supply lines to Haiti are often fragile, even without a devastating natural disaster.
The quake-damaged seaport is "basically shut down," said Farmer, who has 27 years' experience working in Haiti. Air traffic was backed up, he said, with planes jockeying to land at a minimally functioning airport.
UNICEF, the United Nations' children's charity, was amassing supplies in Panama for an airlift. The agency sent one plane with medical kits, blankets and tents to Port-au-Prince on Thursday, but the plane could not land and had to return to Panama.
"It's really a logistics nightmare," Farmer said. "We need to fix the port and open up other land bridges and air spaces where planes and helicopters can land."
The U.N. response has been further hampered by its own losses. Although there's no official body count, U.N. officials said at least 30 of their colleagues in Haiti are known to be dead and 100 to 150 remain missing.