Looting has hampered the relief effort
At least 16 people are now known to have died in flooding which hit Argentina's Santa Fe province earlier this week.
Police say more bodies are likely to be found as the Salado River starts to recede.
A third of the city of Santa Fe remains under water and as many as 100,000 people have been evacuated from their homes.
Dozens of people are still thought to be missing.
On Friday, the Red Cross in Argentina said it was facing security problems in distributing aid in the province - a key farming area.
The only thing I have is the clothes on my back - everything else is underwater
The charity's director, Ariel Kestens, told the BBC there had been incidents of looting and said the Red Cross was having to halt distribution of aid after dusk for safety reasons.
There have been reports of some trucks carrying aid being hijacked by robbers.
Waters have been receding, but many people are waiting out the flooding on the rooftops of their homes, fearing looting.
"The only thing I have is the clothes on my back - everything else is underwater," one flood victim told reporters.
Troops have been helping with the relief effort, distributing food, medicine and clothing to people camped out in school buildings and other makeshift sites.
Many homes were still without water and electricity on Friday, four days after the flooding began.
Governor Carlos Reutemann called the flooding "the worst catastrophe in the history of the province".
"We are going to have to really steel ourselves to get over this," he said.
President Eduardo Duhalde has declared the province a "disaster zone" and announced an emergency aid package worth more than $2m.
The flooding in the low-lying region was so dramatic that Santa Fe City, 390 kilometres (250 miles) north-east of Buenos Aires, effectively became an island, the BBC's Peter Greste in Argentina says.
Santa Fe City, built on the Salado River, has a population of about 400,000.