RIO DE JANEIRO, Brazil (CNN) -- The death toll from flooding in southern Brazil on Thursday climbed to 97, the state news agency said.
Officials said about 19 people remain missing.
Brazilian President Luiz Inacio Lula da Silva flew over some of the flooded areas and proclaimed the disaster one of the worst in the country's history.
"I've never seen anything like this," Lula da Silva said Thursday.
He said he is releasing 1.97 billion reais ($854 million) in aid to the afflicted areas, most notably the state of Santa Catarina.
About 1.5 million people -- one-fourth of the population -- have been affected, and nearly 79,000 residents have been left homeless, civil defense officials said. Two municipalities remain isolated, without basic services such as electricity or any medicines.
Garbage is floating in the streets of some cities, and officials are worried about outbreaks of epidemics.
Rescuers are working to free residents trapped by the collapse of houses due to mudslides. Personnel from all the military branches also are delivering food, medicines and clothing, officials said.
The flooding also is having an economic effect, with bridges, roads, houses and buildings destroyed. The federation of industries said the closing of the port in the Santa Catarina city of Itajai, one of the hardest-hit areas, is costing $33 million a day.
Weather forecasters said the rain should be lessening in Santa Catarina until the weekend but issued an alert for other Brazilian states such as Rio de Janeiro, Sao Paulo and Espirito Santo.
Journalist Fabiana Frayssinet contributed to this report.