Tens of thousands of people in Haiti are still threatened by an outbreak of cholera despite some signs that the epidemic is stabilising, the UN says.
UN humanitarian co-ordinator in Haiti Nigel Fisher said the UN was preparing for a wider outbreak although there were no new signs of it spreading.
The Haitian government earlier said that only six new deaths were reported in the past 24 hours.
A total of 259 people are now known to have died from the disease.
Three hundred new infections have been recorded, taking the total to 3,342, Haiti's health ministry said.
"This is an extremely serious situation and based on experience with epidemics elsewhere it would be irresponsible to plan for anything but a considerably wider outbreak," Mr Fisher said on Monday.
The UN and aid agencies are now also boosting prevention efforts in and around Haiti's capital Port-au-Prince, where some 1.3 million survivors of January's devastating earthquake live in tent camps.
Five cholera cases were detected on Saturday in Port-au-Prince, but they were quickly diagnosed and isolated. Another 20 suspected cases were under investigation, medical aid organisation Medecins Sans Frontieres (MSF) told the BBC.
Haiti has not seen a cholera outbreak for about half a century, and many people are said to be frightened by the news of the outbreak and unsure of what steps to take to avoid the disease.
Poor sanitary conditions make the camps and slums vulnerable to cholera, which is caused by bacteria transmitted through contaminated water or food.
Cholera causes diarrhoea and vomiting leading to severe dehydration, and can kill within 24 hours if left untreated. It is easily treated through rehydration and antibiotics.
Planning for the worst
The director general of Haiti's health department, Gabriel Thimote, confirmed on Monday that the rate of increase in cholera deaths had slowed.
However, the number of infections had increased by 10% since Sunday, rising from 3,015 to 3,342, and aid agencies insisted they would remain on alert.
"We think that the situation is stabilising. That doesn't necessarily mean we have reached a peak," he said.
Agencies battling to contain the disease echoed Mr Thimote's caution.
"To be honest, I believe the death toll will increase in the coming days," said Harold Paul, regional emergency manager for UK aid organisation Christian Aid.
"My sense is that in two weeks the situation will be under control. The death toll will increase in Artibonite, but seems to be contained in Plateau Central. But in Port-au-Prince, let's wait and see."
Michel Van Herp of MSF, medical adviser to the organisation's teams working in Haiti, said 400 people remained in hospital in Saint-Marc, the town at the centre of the Artibonite outbreak.
Another 150 people were being treated in hospital in the town of Mirbalais, along the Artibonite river, he said.
While he conceded that most infections were in the Artibonite region, Dr Van Herp said MSF would remain on alert.
"We are preparing ourselves for the worst case scenario, which is a cholera outbreak in the whole country," he told the BBC.
Previous experience responding to cholera in Latin America in the early 1990s suggested that the disease could spread easily across large areas and could incubate for a number of days before presenting symptoms, Dr Van Herp said.
In Haiti, UN spokeswoman Imogen Wall said most effort was being directed into setting up dedicated treatment centres and making sure people across Haiti were kept informed of the best ways to stem the spread of the disease.
She cautioned that a temporary lull in the increase of infections did not guarantee the crisis was coming to a quick end.
"One day does not mean anything in terms of spread," Ms Wall told the BBC.
The UN's Office for the Co-ordination of Humanitarian Affairs was managing the mass distribution of soap and other basic hygiene items, including bucket with lids to prevent clean water becoming contaminated, she said.
But the UN remained concerned that areas outside of its post-earthquake emergency remit, including the slums of Port-au-Prince, were especially vulnerable to infection.
While diarrhoea is endemic in Haiti, cholera remains unfamiliar to most people, Ms Wall said. Simple precautions including the use of soap in hand-washing were not familiar to most people.
"Everyone has heard about cholera now, but we need to keep pushing the message," she added.
The worst-hit areas of the outbreak are Saint-Marc, Grande Saline, L'Estere, Marchand Dessalines, Desdunes, Petite Riviere, Lachapelle, and St Michel de l'Attalaye.
A number of cases have also been reported in the city of Gonaives, and towns closer to the capital, including Archaei, Limbe and Mirebalais.
Haiti has enough antibiotics to treat 100,000 cases of cholera and intravenous fluids to treat 30,000, according to the UN.