Brazilian authorities have dispatched police to quell looting in some of the worst-hit areas in southern Brazil, where floods and rain-spawned landslides have left at least 97 people dead.

Police arrested several people in the cities of Blumenau and Itajai, two of the hardest-hit areas, for ransacking grocery stores and supermarkets. Officials say that in some areas, people have not had food or water in at least four days.

Civil defense officials estimate that more than 100,000 people remain cut off after several days of heavy flooding in southern Santa Catarina state.

The Brazilian government has pledged hundreds of millions of dollars in aid to emergency relief, including the rebuilding of roads and ports.

Brazilian President Luiz Inacio Lula da Silva flew over the affected areas Wednesday and called the devastation the "worst environmental calamity" the country has ever faced.

Officials say there still is a risk of more landslides. Local politicians have declared states of emergency, urging people to leave their homes and seek shelter at safer locations.

Helicopters - some provided by the government - have rescued more than 1,000 people.

Flooding also cut natural gas supplies after rupturing a pipeline that runs from Bolivia to Brazil.

Some information for this report was provided by AFP, AP and Reuters.