Beleaguered rescue workers struggled early Thursday to find survivors after another mudslide surged into a rain-sodden hillside shantytown, engulfing at least 40 homes in a huge cascade of mud.
The state Civil Defense department said the latest slide unleashed by heavy rains hit in Rio's neighboring city of Niteroi. There was no word on how many were missing, but it was feared dozens were buried under the debris.
Although rain let up some late Wednesday, Alves Souza, commander of the firefighters in the Niteroi rescue operations carried out under electric lights, said the work was moving slowly.
The wet, steep terrain made it dangerous for anyone trapped in the wreckage and those trying to pull victims out, The Associated Press reported.
President Luiz Inacio Lula da Silva urged Brazilians to pray for the rain to stop. He said: "When the man upstairs is nervous and makes it rain, we can only ask him to stop the rain in Rio de Janeiro so we can go on with life in the city."
Thousands of motorists were stranded on highways blocked by rising water, Scottish Daily Record reported.
Flooding from the heaviest downpours in almost half a century in southeastern Brazil have killed more than 133 people since Monday.
Flooding has been so intense that authorities urged area residents to remain indoors and not venture downtown, where streets were impassable. Rescue authorities also said 135 were injured and 53 were missing.
Rio's mayor Eduardo Paes said traffic had improved after the rains turned roads into lakes and left commuters and residents stranded. He added that the city's fire department had stepped up searches for dozens of people missing, according to Telegraph.co.uk.