Floodwaters in Haiti are starting to recede as aid agencies struggle to bring relief to thousands of people in the wake of tropical storm Jeanne.
Many in Gonaives may not have eaten for nearly a week
In the city of Gonaives desperate crowds have been trying to get food and water, amid growing fears of disease.
Floods and landslides have left more than 1,000 people dead. Officials warn the final toll could be twice as high.
Jeanne, now a hurricane, is expected to strike the northern Bahamas before heading for Florida this weekend.
UN peacekeepers who have been deployed to assist the interim government are playing a crucial role in making sure rising tensions do not turn into outright violence, reports the BBC's Dan Griffiths in Gonaives.
People who may not have had food for days have been gathering around relief centres, hampering the handing out of supplies.
At one warehouse in Haiti's third largest city, there were angry scenes as several hundred people surged against the gates of the building, desperate to get inside, our correspondent says.
Many homes have been ripped apart, forcing the owners to live on the streets or on the rooftops of houses that are still intact.
A number of children, abandoned or orphaned, were seen
roaming around the city, the International Committee of the Red Cross (ICRC) told Reuters news agency.
"I think it's fair to say that the situation is tense
because people are desperate," UN World Food Programme (WFP)
spokeswoman Anne Poulsen said.
"Many have not eaten since
Saturday night or Sunday morning."
The authorities are continuing to bury victims of the floods in mass graves.
Corpses have been dumped in a pit near Gonaives in an attempt to prevent the spread of disease, while unclaimed bodies continue to litter the city.
Only a couple of dozen bodies have been identified and more than 1,000 people are still missing.
Correspondents say limes have become popular as a way of alleviating the stench.
The roads are covered in a thick coat of mud and there is a smell of raw sewage in the air.
Survivors have to drink and cook with water from ditches containing rotting bodies and sewage.
"It's a critical situation in terms of epidemics, because of the bodies still in the streets, because people are drinking dirty water and scores are getting injuries from
debris - huge cuts that are getting infected," Francoise Gruloos, Haiti director for the UN Children's Fund was quoted as saying by the Associated Press news agency.
Haiti is chronically vulnerable to flooding and mudslides because of widespread deforestation.
Appealing for international support, UN Secretary General Kofi Annan said he was "deeply saddened by the heavy loss of life and destruction".
In the neighbouring Dominican Republic - which has retained much of its forest cover - the death toll from Jeanne was 19.