BBC News with Fiona McDonald.

The United Nations in Geneva says the earthquake in Haiti is the worst disaster ever confronted by the organization in terms of logistics, because of the complete collapse of local government and infrastructure. It said Haiti's airport was clogged, its roads blocked, and hospitals had few if any doctors. Tens of thousands of victims had still received no aid whatsoever four days after the quake. In the capital Port-au-Prince, huge lorries have been helping to clear the streets of rubble, so the assistance can get through. And terrible though the conditions are there, it's feared things could be even worse elsewhere in Haiti where even less help has so far arrived. Our correspondent Mark Doyle went to see.

The scene in an hour's drive west of Port-au-Prince apocalyptic. Almost every single building on the road I am driving on now has been flattened. Reinforced concrete roofs have fallen to the floors below or have jammed into the ground at crazy angles. The destruction here is even more dramatic than the dreadful conditions in the capital. People have fled to the surrounding sugarcane fields or into mangrove swamps anything to get away from the nightmare of the falling buildings. I've seen a long line of people queuing up at a single working water tap. Tens of thousands are living in the opening church compounds, school playgrounds and market places. The population here are in profound shock.

Reports coming out of Port-au-Prince say a crowd of about a thousand people have been involved in a violent fight over goods in one of the city’s central commercial streets. A photographer for the Reuter News Agency said that a group of men armed with knives, ice picks and hammers fought one another over clothing, toys and any other items they could find in destroyed houses and shops. The incident calms hours after a senior United Nations official Alien Edward warned of the security threat from the delay in the distribution of aid.