Teresopolis (Brazil), Jan 13 (Agencies): Rescuers searched through layers of mud on Thursday for survivors and bodies after freakishly heavy rains caused landslides and torrents to slice through three towns near Rio de Janeiro, killing at least 356 people.

Media said the calamity, devastating the mountain towns of Teresopolis, Petropolis and Novo Friburgo, was Brazil's worst natural disaster in 43 years.

President Dilma Rousseff was to fly over the zone today. Her government has released USD 470 million in initial emergency aid and sent seven tons of medical supplies.

The death toll from the area, known as the Serrana, has risen progressively as rescuers spread out into remote hamlets.

Destroyed roads and bridges meant that access in many cases was possible only with one of seven helicopters deployed to help rescue efforts. Telephones and power systems had collapsed in several locations.

The catastrophe struck before dawn on Wednesday, as families were asleep in their homes.

Tropical rains are common at this time of year in southeastern Brazil. But they were suddenly intensified by a cold front, bringing weeks' worth of water crashing down in a matter of hours.

Houses collapsed, hillsides gave way and rivers broke their banks.

"One woman tried to save her children but her two-month-old baby was carried away by a torrent like a doll," said Angela, a 55-year-old resident of Teresopolis.