People in southern Brazil have described the unprecedented devastation wreaked by flooding and overflowing rivers which have left swathes of the area under water.
The floods are the worst natural calamity ever to hit the state of Rio Grande do Sul, officials say.
At least 95 people have died and more than 130 are still missing.
An estimated 1.4 million people have been affected by the floods and aid workers are struggling to provide them with drinking water.
Days of torrential rain caused rivers to overflow and have submerged entire towns.
The capital of Rio Grande do Sul, Porto Alegre, is among those affected.
The city of 1.3 million inhabitants has been almost totally cut off by the floods.
An estimated 80% of its population do not have access to running water after five of the city’s six water treatment plants ceased working.
Suzan, a resident of Porto Alegre, said that people in the city had “never experienced anything like it”.
“There are thousands of people who lost their houses. Now we don’t have water anywhere,” she said in a voice message she sent to the BBC.
“My mother-in-law is 90 years old and she had to be carried by the rescuers. It’s unbelievable what is going on here,” she added.
The city’s mayor has rationed drinking water and city officials are distributing water in tanker trucks.
The work of aid and rescue teams has been hampered by criminal gangs, which have been stealing their boats.
“Jet skis and houses were looted. This is deplorable and must be denounced,” a presidential spokesman said.
The city authorities have called for anyone who owns “any kind of boat” to put it at the disposal of emergency teams as thousands of residents still need to be rescued from neighbourhoods cut off by the water.
One resident, Alexander Ramos, told AFP news agency that he had been forced to leave his home because “everything had been washed away by the flood”.
“We tried to wait as long as we could, but there was no chance, the army came and rescued us, as well as our dogs.”
Some families are leaving the city on foot. “We’ve been without food for three days,” one man told Reuters news agency.
“I’m with people I don’t even know, I don’t know where my family is,” he added.
The latest estimates suggest 155,000 people have been left homeless.
The governor of the region has warned that torrential rainfall is due to resume this week.