Nova Friburgo , Brazil ( CNN ) -- The death toll from devastating flooding in Brazil continued to rise Sunday , surpassing 600 , the government said . At least 655 deaths were reported in a mountainous region of Rio de Janeiro state , northeast of the city of Rio . Other states in the South American country have also seen heavy rainfall . Last week , authorities in neighboring Sao Paulo state said 24 people had been killed by flooding . Forecasters there said late Sunday that an approaching cold front could bring more flooding and landslides . Most of the deaths in Rio de Janeiro state were reported in the cities of Nova Friburgo and Teresopolis , with 302 and 276 fatalities , respectively . The state 's health and civil defense department reported 58 fatalities in the town of Petropolis and 19 in Sumidouro . Officials in that office also warned residents of the risk of waterborne diseases . Several thousand vaccines against tetanus and diphtheria have been distributed , they said . Rescuers have not been able to reach some hard-hit areas , and many more people are feared dead . The rain is predicted to continue for several days in areas already submerged in water or slathered with mud . Members of the army entered parts of Teresopolis and were able to rescue 110 families . Thousands of families are still living on mountain slopes or on riverbanks and face extreme risk of being washed away . One resident described the disaster as a tsunami that fell from the sky . In a statement , Rio Gov . Sergio Cabral said he had a panic attack when he was traveling to Nova Friburgo and saw a devastated mountainside . Outside a makeshift morgue in Teresopolis , a crowd of people waited for their turn to identify loved ones . Marco Antonio Siqueira Costa said the last time he saw his brother , sister-in-law and niece was a few days ago , before mud buried their house . `` I think that last meeting was God 's way of granting us a farewell , '' he said . Residents in the city donned masks and helped clean streets or deliver first aid . Others combed the city searching desperately for missing loved ones . Red Cross volunteer Maria Helena de Jesus was helping with first aid . `` You have to almost have a heart of stone , '' she said . `` It was very difficult . '' Teresopolis Mayor Jorge Mario Sedlacek declared his city a natural disaster area . President Dilma Rousseff flew over flood-affected areas last week and landed in Friburgo , the agency said . The floods are her first test as president . She trudged through mud to talk to residents in a neighborhood where four of seven firefighters trying to rescue people had been buried under mud . The other three were pulled out alive . `` We are going to take firm action '' to help the devastated areas , Rousseff said . Brazilian authorities have been criticized for a lack of disaster planning , and for and allowing people to build homes in areas known to become treacherous in the rainy season . They are under increasing pressure to show a strong response . Brazil is scheduled to host the World Cup in 2014 and the Olympics in 2016 . Journalist Fabiana Frayssinet contributed to this report .
Forecasters say more flooding and landslides could hit Sao Paulo state . At least 655 deaths are reported in Rio de Janeiro state . Officials warn of the risk of waterborne diseases . Troops arrive to help rescue those who are trapped .