In one of the country's worst natural disasters, rivers of mud tore through towns in the mountainous Serrana region outside Rio de Janeiro, leveling houses, throwing cars atop buildings and leaving thousands of people seeking shelter.

"The rain did not stop at dawn and is continuing in the morning, which is making the rescue efforts more difficult," said Lieutenant Rubens Placido, a fireman in the hard-hit town of Nova Friburgo. "The number of deaths is going to rise quite a bit. There are still a lot of people buried."

The flooding killed at least 529 people, according to local and state authorities, but rescuers are uncovering more victims buried under wrecked homes and toppled buildings. More than 13,500 people have been left homeless. [ YAHOO NEWS ]