* Heavy rains spark landslides, floods in southern Brazil

* Three firemen missing, buried by landslide

* Rescuers still reaching remote areas (Updates death toll)

RIO DE JANEIRO, Jan 12 (Reuters) - Floods and landslides devastated mountain towns near Rio de Janeiro and killed dozens, bringing the death toll on Wednesday from heavy rains in Brazil’s south to at least 257.

At least 130 people were killed in Teresopolis, about 62 miles (100 km) north of Rio, town officials said, after hillsides and riverbanks buckled under the equivalent of a month’s rainfall in 24 hours, sending water and mud surging through communities.

At least 20 people were killed in the city of Petropolis, and 107 in the town of Nova Friburgo, state officials said in an e-mailed statement.

The rains sweeping southeastern Brazil also killed 13 people in Sao Paulo state on Tuesday and snarled transport in the country’s financial capital.

About 50 people were believed missing just in Teresopolis, the city’s mayor, Jorge Mario, told Globo television.

“Rescue teams are still arriving in the areas that have been worst affected,” he said, adding that about 1,000 people had been left homeless. “It’s the biggest catastrophe in the history of the town.”

Thousands of people in the picturesque area, known as the Serrana region, were isolated by the flood waters and cut off from power and telephone contact.

The downpour caused at least one river to burst its banks, submerging cars and destroying houses in Teresopolis, television images showed.

“I saw six bodies on my street,” 53-year-old Teresopolis resident Antonio Venancio, whose house was inundated with mud but remained standing, told Reuters by telephone.

“We just don’t know what to do in the face of something so horrible.”

Rio state Governor Sergio Cabral said in a statement he had asked the Navy for aircraft to take rescue crews and equipment to the region, which was partially cut off from Rio by road.

In Nova Friburgo, three fireman were missing after being buried by a mudslide while they tried to rescue victims, according to fire officials. One three-story house collapsed on Tuesday, killing three people, including two children.

Buses and trucks were shown stranded on streets with flood waters reaching up to their windows.