Dynamiting a dyke helped reduce water levels
Authorities in the Argentine province of Santa Fe have blown up a dyke to help lower water levels following the most severe flooding in the province's history.
At least nine people are now known to have died, and at least 50,000 people were evacuated earlier in the week.
The Argentine Government has announced it is creating a special committee to preserve order in the region amid fears of looting.
The committee is to include Justice Minister Juan Jose Alvarez and the head of the gendarmerie, Jorge Della Bianca.
The World Bank will offer the stricken province 350m pesos ($110m) in credits to help deal with the catastrophe, President Eduardo Duhalde announced on Thursday.
President Duhalde, who described the floods as a "national catastrophe", earlier announced an emergency aid package worth over $2m.
Local civil defence officials said in some areas the rivers had risen by as much as 50 centimetres (20 inches) in 12 hours, with the Salado river almost two metres (six feet) above normal.
"It was so fast, nothing like it has ever happened," said local resident
Provincial governor Carlos Reutemann said the floods were the worse since Santa Fe City was founded in 1573.
The flooding in the low-lying region was so dramatic that the city, 390 kilometres (250 miles) northeast 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.
A third of Santa Fe Province, about 200,000 hectares, is under water.
In Entre Rios province, at least 1,500 people have been evacuated.
Local health officials say the floods have also caused a dramatic increase in hepatitis and gastro-intestinal illnesses.
They have said they will start vaccinating people to avoid the spread of diseases.