But into the third day following the 7.0-magnitude quake, the global helping hand was slowed by a damaged seaport and an airport that turned away civilian aid planes for eight hours Thursday because of a lack of space and fuel.
Aid workers have been blocked by debris on inadequate roads and by survivors gathered in the open out of fear of aftershocks and re-entering unstable buildings.
"The physical destruction is so great that physically getting from point A to B with the supplies is not an easy task," Casella, the WFP spokeswoman in Geneva, said at a news conference.
Across the sprawling, hilly city, people milled about in open areas, hopeful for help, sometimes setting up camps amid piles of salvaged goods, including food scavenged from the rubble.
Small groups could be seen burying dead by roadsides. Other dust-covered bodies were being dragged down streets, toward hospitals where relatives hoped to leave them. Countless dead remained unburied, some in piles. Outside one pharmacy, the body of a woman was covered by a sheet, a small bundle atop her, a tiny foot poking from its covering.
Aid worker Fevil Dubien said some people were almost fighting over the water he distributed from a truck in a northern Port-au-Prince neighborhood.
Elsewhere, about 50 Haitians yearning for food and water rushed toward two employees wearing "Food For The Poor" T-shirts as they entered the international agency's damaged building.
"We heard a commotion at the door, knocking at it, trying to get in," said project manager Liony Batista. "'What's going on? Are you giving us some food?' We said, 'Uh-oh.' You never know when people are going over the edge."
Batista said he and others tried to calm the crowd, which eventually dispersed after being told food hadn't yet arrived.