Brazil's supreme court is to rule today on whether former president Luiz Inacio Lula da Silva should start a 12 year prison sentence for corruption, potentially upending this year's presidential election.
The court showdown in the capital Brasilia is a key battle for Brazil's deeply polarised electorate ahead of the October polls, in which Lula is currently the heavy favourite, despite his legal problems.
Late yesterday, up to 20,000 people demonstrated in Brazil's biggest city, Sao Paulo, to demand Lula go to prison and be barred from the election.
More protests -- for and against Lula -- were planned in Brasilia today, with demonstrators separated by a metal barrier and heavy police presence.
The head of the army, General Eduardo Villas Boas, tweeted that the military shared Brazilians' "desire for the repudiation of impunity."
Villas Boas also asked "who is really thinking about the good of the country and future generations and who is only worried about personal interests?"
"We want Brazil to be freed of this shameful corruption. Imprison Lula and let Brazil turn the page," said Mara Massa, 67, at the protest in Sao Paulo, where the crowd chanted "No more Lula!"
Ahead of Villas Boas' unusual comments, an army reservist general lashed out in Estadao newspaper that a Supreme Court ruling that freed Lula would "induce" violence and "fratricidal conflict."
General Luiz Gonzaga Schroeder Lessa, who has a history of making provocative remarks, even appeared to threaten a coup, saying an eventual Lula election victory would "leave no recourse but an armed reaction. The armed forces would have to restore order."