SAO PAULO - The death toll from heavy rains in the southern Brazilian state of Rio Grande do Sul has risen to 56, with 67 missing, 32,900 evacuated and at least 356,000 without electricity, the Civil Defense agency said Saturday.

Heavy rains in the state for nearly a week have so far affected 281 municipalities, causing rivers to overflow and putting Porto Alegre, the state capital, almost underwater, said the agency.

"The numbers could change dramatically in the coming days as we reach the site and identify other lost lives," State Governor Eduardo Leite said.

Brazilian President Luiz Inacio Lula da Silva has ordered the opening of an emergency office in Porto Alegre to facilitate technical and financial aid, after sending 100 members of the national force, an elite police force, on Friday to assist in the rescue mission.

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Rio Grande do Sul is a key point in the land transport of the Southern Common Market (Mercosur) and also one of the main producers of rice, soybeans and meat in Brazil, whose economy has been held back for a week due to the weather.