PORT-AU-PRINCE, Haiti -- Desperately needed aid from around the world slowly made its way Thursday into Haiti, where supply bottlenecks and a leadership vacuum left rescuers scrambling on their own to save the trapped and injured and get relief supplies into the capital.
The international Red Cross estimated that 45,000 to 50,000 people were killed in Tuesday's magnitude-7.0 earthquake.
President Barack Obama announced that ''one of the largest relief efforts in our recent history'' is moving toward Haiti, with thousands of troops and a broad array of civilian rescue workers flying or sailing in to aid the stricken country -- backed by more than $100 million in relief funds.
To the Haitians, Obama promised: ''You will not be forsaken.''
The nascent flow of rescue workers showed some results: A newly arrived search team pulled U.N. security worker Tarmo Joveer alive from the organization's collapsed headquarters, where about 100 people are still trapped. He stood, held up a fist in celebration, and was helped to a hospital.
There are easily hundreds, and perhaps thousands, of people trapped, living or dead, in collapsed buildings. No one knows for certain. Friends and relatives have had to claw at the wreckage, often with bare hands, to try to free them.
Many dead bodies that were recovered still lay in the street, often covered by a white cloth, in 81-degree heat.
Some people dragged the dust-covered dead along the roads toward the morgue, where people came to hunt for relatives in a macabre sea of hundreds of bodies just a few feet from where badly injured victims awaited a doctor from the neighboring hospital.
Planes from China, France, Spain and the United States landed at Port-au-Prince's airport, carrying searchers and tons of water, food, medicine and other supplies -- with more promised the Western Hemisphere's poorest nation. The Red Cross has estimated 3 million people -- a third of the population -- may need emergency relief.
The flow into the capital's damaged airport was so great that the Federal Aviation Administration halted all civilian flights from the United States to Port-au-Prince for a time Thursday because there was no room on the ground for more planes and not enough jet fuel for planes to go back, an official at the FAA said, speaking on condition of anonymity because he was not authorized to talk publicly. Civilian relief flights were later allowed to resume.
It took six hours to unload a Chinese plane due to a lack of equipment -- a hint of possible bottlenecks ahead.
''We don't have enough handling equipment or the people to run it,'' said U.S. Air Force Col. Ben McMullin, part of the team handling traffic at the airport. ''We're trying to control the flow of aircraft.''
In Geneva, Red Cross spokesman Jean-Luc Martinage said the Haitian Red Cross estimated 45,000 to 50,000 people were killed, based on reports from its volunteers in Port-au-Prince.
There seemed to be little official Haitian presence in much of the capital -- or at the airport, where the U.S. Southern Command was controlling flights from a fenced-off building at the end of the runway. The facility's usual tower had collapsed.
McMullin said about 60 planes carrying 2,000 people had landed between Wednesday, when the airport reopened, and noon Thursday.