Army soldiers used boats, trucks and helicopters to tote food and water to scores of cities and towns isolated by floods that have killed at least 30 people and left nearly 200,000 homeless.
But in an ominous sign that worried civil defense officials, rain continued to fall across a vast region stretching from the Amazon jungle to the northeastern Atlantic coast and meteorologists predicted the bad weather could last for weeks.
Isolated looting was reported in communities cut off by flooding, and some areas were experiencing their heaviest rainfall in more than two decades, officials said.
In three Amazon states, at least 3,000 Indians near rivers that overflowed fled to higher ground or into the jungle after seeing their crops of manioc, bananas and potatoes destroyed, said Sebastiao Haji Manchiner, executive secretary of the Brazilian Amazon Indigenous Organization.
In the hardest-hit state of Maranhao, some rivers were rising as much as 30 centimeters per day, destroying bridges and making it too dangerous for relief workers to navigate waterways.
“There are some places where the water is so high that not even a boat can get to people,” said Brazilian army Lt Ivar Araujo, in charge of 200 soldiers trying to help citizens in two towns where homes were submerged to their roof tiles and hundreds packed into shelters in gyms and schools.