At least 91 people have died and up to 117,000 have been forced out of their homes in the poor north-eastern states of Pernambuco, Bahia and Piaui.

Luis Inacio Lula da Silva said he was shocked by the scale of the damage in a region more used to water shortages.

He promised emergency food and shelter for the homeless and pledged funds to rebuild some 4,000 destroyed homes.

With more rain forecast, the worst-affected states say they have not been given enough emergency funds to deal with the immediate aftermath.

Emergency workers have been scrambling to rescue people trapped in towns that have become islands, provide temporary accommodation in schools and shelters and tend to dozens of injured.

Most of the victims either drowned or were crushed to death when mudslides caused their homes to collapse.

About 4,200 houses have now been destroyed and a further 112,800 damaged since late December.

'Slow and bureaucratic'

President Luis Inacio Lula da Silva - or Lula, as he is better known - said the floods had disproportionately affected the poorest Brazilians whose homes line river banks in low-lying areas.

On a visit to the region, he said his government would distribute food, drinking water, drugs and tents to victims of the flooding.

"We will do all that we can to minimise your immediate suffering and then, in a second phase, improve conditions so that you will not be victimised by floods again," he told people in Piaui.

On Wednesday, a Brazilian Air Force C-130 Hercules aircraft was distributing 18 tonnes of food around the region.

Some states complain of insufficient funding to help survivors

But governors of the states affected have complained that the 32 million reais ($11m) of funding they have received from two ministries was not enough.

"It's a small amount, and it's coming slowly," said Jarbas Vasconcelos, governor of Pernambuco, according to Globo news.

"We don't question that there's good will, and the intention to help, but the process is slow and bureaucratic," he said.

The wealthier, southerly state of Sao Paulo has also been badly hit, with 16 bridges washed away and motorists swept off roads that turned into rivers, according to Reuters news agency.

It said 29 people had died there.