Thousands of Haitians are leaving their devastated capital, Port-au-Prince, fleeing what has become a mass grave. Bodies lie rotting in the streets four days after Tuesday's 7.0 earthquake.
A Haitian government minister says that the bodies of 50,000 people have been collected so far.
The BBC reports that people are leaving in desperation because food and water are not getting through to them. Some have been scavenging in the rubble for something to eat.
The government believes the final death toll will be between 100,000 and 200,000, interior minister Paul Antoine Bien-Aime says, though the exact number will never be known. The Pan American Health Organisation says it could be as high as 100,000.
The United Nations says that about 300,000 people are homeless, and that up to half the buildings in Port-au-Prince have been destroyed or damaged.
Other towns severely damaged too
Other Haitian towns and cities have been badly hit too. Petit Goave, Grand Goave and Leogane are thought to have suffered severe damage, and Mark Stuart, who runs an orphanage in Jacmel, a city of 60,000 people on the south coast, says many thousands have died there.
Jacmel is about 32 kilometres from the capital but aid can't get through because the road has collapsed. The hospital has been destroyed, the city is running out of medicine and food, and people are desperate for help, Mr Stuart says.
The orphanage children are sleeping outdoors, he says.
Little sign seen of co-ordinated relief
Anger is reportedly growing in Port-au-Prince over the time it is taking to distribute aid. The BBC reports that there is little immediate sign of a co-ordinated relief effort, with survivors still having to beg for food and water.
Unicef spokesperson Tamar Hahn, who has just arrived in Haiti, says the situation is desperate. Ample aid resources have been allocated for the immediate relief effort, she says, but it's difficult to distribute them.
The UN says its main problem is moving supplies from warehouses to where they are needed, because of the extent of the destruction.
Unicef's executive director in New Zealand, Dennis McKinlay, says the level of destruction presents a huge logistical challenge. He says a first load of relief supplies has been airlifted to the area, with another soon to follow.
Prepared for possibility of rioting
With reports of armed gangs looting, US authorities are preparing for the possibility of rioting. Up to 10,000 US troops are expected to arrive by Monday to help distribute aid and maintain security.
Brazil is sending guns with rubber bullets and other non-lethal weapons.
UN special envoy Leslie Voltaire acknowledges that the authorities are aware that emotions could soon boil over. If food and water doesn't arrive rapidly, he says, there will be more problems in the streets.
Sporadic gunfire has been heard across the capital. Thieves are reportedly roaming the streets at night.
UN launches appeal for $720 million
The United Nations has launched an appeal for $720 million, which will be used, UN humanitarian chief John Holmes says, to help three million people in Haiti for six months.
About $460 million has been pledged so far for the relief effort, but only part of that sum will be included in the emergency appeal.
More than 300 UN personnel are missing, feared dead.
UN Secretary-General Ban Ki-moon will travel to Haiti on Sunday to show solidarity with the people and assess for himself the humanitarian aid effort and the scale of the disaster.
US Secretary of State Hillary Clinton was also due to arrive on on Saturday.