Five days after a powerful earthquake killed at least 2,189 people in Haiti help is trickling in, but struggling people say they need it more quickly.
The poorest country in the Americas is in urgent need of medical, food and sanitation assistance, experts say.
Rescue crews are still digging through rubble in a search for survivors, as the stench of death fills the air.
"We are preparing for a public health disaster," says Nadesha Mijoba of the Haitian Health Foundation.
"The sanitation situation is quite critical... it is our hope that we don't have an outbreak of cholera," Ms Mijoba also warned BBC News.
Since the 7.2 magnitude earthquake hit the island on Saturday, the US military has transported at least 200 severely injured people to hospital.
Despite rainy conditions, many people have been sleeping outside due to fears that aftershocks could cause more buildings to collapse.
"We are afraid to go inside, so we sleep on the ground in the street," one person in the hard-hit region of Les Cayes told BBC News.
"I don't have a job, I don't have water, I don't have food. My house was destroyed, there is nothing," said another woman.
Around 53,000 homes were completely destroyed in the quake, with about 77,000 more damaged.
The US Army is preparing to set up a field hospital in Les Cayes. The US and British Navy are also each sending ships to help with rescue and recovery efforts.
Doctors are struggling to treat the more than 12,200 people who have been injured. Hundreds are still missing, and presumed trapped under the rubble.
Rescue workers had had to contend with armed gangs who attacked aid convoys.
The UN Office for the Coordination of Humanitarian Affairs said on Tuesday that following negotiations, the gangs had agreed to let aid through.
But a major Port-au-Prince hospital closed for two days after two doctors were kidnapped by criminals. A pregnant mother and her baby died while waiting for one of the captured doctors, who was meant to be on his way to perform an emergency Caesarean delivery.
The earthquake compounds problems facing the impoverished nation, which is already reeling from a political crisis following the assassination of its president last month.
Haiti has been hit by a series of natural disasters in the past, including Hurricane Matthew in 2016.
The deadliest was the 2010 earthquake which killed more than 200,000 people and caused extensive damage to the country's infrastructure and economy.