Fresh rains in Brazil have sparked fears that the death toll from floods and mudslides triggered by the worst thunderstorms in 30 years, could rise.

Rain was coming down again early on Wednesday in Rio de Janeiro and neighbouring city Niteroi, where at least 95 people were killed after 15 hours of rain triggered the deadly floods and mudslides, officials said.

With transport and communications in Rio all but shut down, Eduardo Paes, the mayor, ordered all schools closed and urged workers to stay home and not visit the downtown area which was inundated with water. Most businesses were also shuttered.

"All the major streets of the city are closed because of the floods," Paes said in a statement.

"Each and every person who attempts to enter them will be at enormous risk."

The rains caused flights in and out of the city to be cancelled or delayed, and schools were closed.

Officials said floodwaters started landslides on the hilly metro area where 16 million people live.

Nowhere to go

Al Jazeera's Lucrecia Franco, reporting from Rio de Janeiro, said most of the casualties were caused by mudslides.

"Ten thousand houses remain at risk mostly in the slums, with one fifth of the population living in shacks that are vulnerable. So the situation is critical," he said.

"The mayor has urged people to leave the risk areas but they have nowhere to go.

"It is impossible to more around the city the streets are rivers. He has told them not to go to risky areas but they live on risky areas."

In January, scores of people were killed in landslides in Rio de Janeiro state, many in the island resort of Ilha Grande when a hillside collapsed after torrential rains.