The International Red Cross estimates 45,000 to 50,000 people were killed in Tuesday's 7.0 Richter scale earthquake in Haiti, based on information from the Haitian Red Cross and government officials, the AP reported on Jan. 15. Hard-pressed recovery teams have resorted to using bulldozers to transport loads of dead.

LWorries mounted, meanwhile, about food and water for the survivors. "People have been almost fighting for water," said aid worker Fevil Dubien.

From Virginia, France and China, a handful of rescue teams were able to get down to work, scouring the rubble for survivors. In one "small miracle," searchers pulled a security guard alive from beneath the collapsed concrete floors of the U.N. peacekeeping headquarters, where many others were entombed.

However, uncounted bodies littered the streets in the heat and arms and legs reached from the ruins. Outside the General Hospital morgue, hundreds of collected corpses blanketed the parking lot, as the grief-stricken searched among them for loved ones. Brazilian U.N. peacekeepers were trying to organize mass burials.

"They want us to provide them with help, which is, of course, what we want to do," said David Wimhurst, spokesman for the U.N. peacekeeping mission. But they see U.N. vehicles patrolling the streets to maintain calm, and not delivering aid and "they're slowly getting more angry and impatient."

In Washington, President Barack Obama announced "one of the largest relief efforts in our recent history," starting with $100 million in aid. The U.S. Southern Command reported the first 100 of a planned 900 paratroopers of the 82nd Airborne Division landed in Haiti from North Carolina on Thursday to support disaster relief, to be followed this weekend by more than 2,000 Marines. The American troops "will relieve pressure" on overworked U.N. elements, Wimhurst said.

From Europe, Asia and the Americas, other governments, the U.N. and private aid groups were sending planeloads of high-energy biscuits and other food, tons of water, tents, blankets, water-purification gear, heavy equipment for removing debris, helicopters and other transport, and teams of hundreds of search-and-rescue, medical and other specialists.

However, global aid faces delays from the poor infrastructure. About 60 aid flights had arrived by midday on Thursday, but were stalled at the overwhelmed Toussaint L'Ouverture International Airport. At midday, the Federal Aviation Administration said it was temporarily halting all civilian flights from the U.S. at Haiti's request because the airport was jammed and jet fuel was limited for return flights. The control tower had been destroyed in the earthquake, complicating air traffic. Civilian relief flights were later allowed to resume.

"There's only so much concrete" for parking planes, U.S. Air Force Col. Buck Elton said at the airport. "It's a constant puzzle of trying to move aircraft in and out."

Teams that managed to land had to navigate Haiti's roads, sometimes blocked by debris or by quake survivors seeking safe open areas in the wake of aftershocks. The U.N. World Food Program said the quake-damaged seaport made ship deliveries of aid impossible.