SAO PAULO — The death toll rose to 143 from the worst extreme weather to ever hit south Brazil's Rio Grande do Sul state, with 125 people missing and more than 600,000 evacuated, the Civil Defense agency said Sunday.

In two weeks of record rainfall that has unleashed flooding and mudslides across the state, 446 towns have witnessed dramatic scenes of survivors rescued from floodwaters, including in the state capital Porto Alegre, where the Guaiba River burst its banks, inundating more than half of the city.

The National Institute of Meteorology has forecast more heavy rains through Monday in Brazil's southernmost state, which borders on Argentina and Uruguay

READ MORE: Brazil floods leave 150,000 homeless, scores dead or missing

Downpours began on April 29 and continued Sunday, erasing hopes of floodwaters receding, and raising the number of the displaced from about 441,000 on Saturday to 618,550 on Sunday.

The National Institute of Meteorology has forecast more heavy rains through Monday in Brazil's southernmost state, which borders on Argentina and Uruguay.

READ MORE: Death toll from southern Brazil rainfall rises to 78, many still missing

Governor Eduardo Leite said this week it will take some 19 billion reais ($3.7 billion) to rebuild Rio Grande do Sul after the floods.