RIO DE JANEIRO (Reuters) -The death toll from heavy rains in Brazil's Rio Grande do Sul state rose to 143, the local civil defense government body said on Sunday, up from 136 in the previous day, while another 131 people remain unaccounted for.

On Saturday evening the government announced around 12.1 billion reais ($2.34 billion) in emergency spending to deal with the crisis that has displaced more than 538,000 people in the state, out of a population of around 10.9 million.

With this new money, more than 60 billion reais in federal funds has already been made available to the state, said the federal government in a statement on Saturday.

Brazil's President Luiz Inacio Lula da Silva said the state will rebuild what was destroyed.

"We know that not everything can be recovered, mothers have lost their children and children have lost their mothers," said Lula on social media X, in a statement to mark Mother's Day.

On Saturday, U.S. President Joe Biden issued a statement, saying that his administration is in contact with Brazil's government to provide assistance.

"Our thoughts and prayers are with the people impacted by this tragedy and the first responders working to rescue and provide medical care to families and individuals," said Biden.

More rain is expected for Sunday, filling rivers that were already full or overflowing, weather forecaster Metsul said on Saturday evening.

The state is at a geographical meeting point between tropical and polar atmospheres, which has created a weather pattern with periods of intense rains or drought.

Local scientists believe the pattern has been intensifying due to climate change.

($1 = 5.1619 reais)

(Reporting by Fabio Teixeira; Editing by Josie Kao and Nick Zieminski)