The focus of Brazil's deepening political crisis shifts to the streets on Sunday with protests for and against the ruling Workers' Party to be held just days after prosecutors called for the arrest of former president Luiz Inácio Lula da Silva for corruption.
On Thursday evening São Paulo state prosecutors said Mr Lula's detention was necessary "to maintain order in society", a day after they formally charged him with crimes connected to an alleged bid to conceal ownership of a luxury apartment.
In an explosive text, they said without preventative custody Mr Lula would use “all his violent network of support” to impede the investigation, in an apparent allusion to the former president’s warning that he would take his Workers’ Party militants on to the streets in order to confront the investigations into his activities.
A judge must authorise the prosecutors’ request before it can be carried out. Their move was widely criticised as an overreach that risks further polarising an already inflamed political situation.
Commentators said it also risked destabilising the broader investigation by federal prosecutors into corruption at state-controlled oil giant
; investigators say they have found strong indications that Mr Lula materially benefited from the multibillion euro scheme.
Mr Lula's defenders seized on the prosecutors' request as further evidence of what they claim is a campaign by public prosecutors to destabilise the ruling Workers' Party government of President Dilma Rousseff by attacking the iconic leader who was elected Brazil's first working class leader in 2002. Party leaders are now said to be lobbying Mr Lula to accept a ministry in Ms Rousseff's government, which would provide him with immunity from arrest.
Though the Workers’ Party is mobilising its militants and allies in trade unions and social movements to take to the streets in defence of the two leaders, its protests are set to be overshadowed by Sunday’s anti-government marches being organised online and backed by the country’s main opposition party.
The biggest of these is to be held in the opposition stronghold of São Paulo, where hundreds of thousands of people have already committed on Facebook to take part in a rally on the city’s main avenue.
With public opinion inflamed by mounting evidence of widespread corruption during 13 years of Workers’ Party rule, as well as a punishing economic recession, the rallies are expected to be the largest since over one million people came out onto the streets across the country a year ago to demand Ms Rousseff’s removal from office.
Organisations linked to the Workers’ Party were prohibited from calling a counter-demonstration at the São Paulo rally in order to avoid clashes, but party militants are planning events elsewhere across the country with some threatening on social media to disrupt the march in São Paulo.
“Sunday will be a good indicator of where we are heading,” says Glauco Peres da Silva, professor of political science at the University of São Paulo.
“We will see if we are going to have confrontations and if so which of the two sides manages to portray itself as the victim.”
Turnout at the anti-government demonstrations, especially away from the opposition bastion of São Paulo, will also be influential in deciding the future of the effort to impeach Ms Rousseff slowly working its way through the congress in Brasília.
It looked to have lost steam at the start of the year but the revelations about Mr Lula’s property dealings and indications that Ms Rousseff’s presidential campaigns were illegally financed by money looted from Petrobras have weakened her support base among allied parties.
In a party congress to be held on Saturday, her main coalition partner, the Democratic Movement of Brazil, is expected to declare its "independence" from her government. The likely move is designed to allow the country's biggest party to hold on to the six ministries it controls, but free its congressional delegation to vote in favour of impeachment.
That could see the party's leader, Ms Rousseff's estranged vice-president Michel Temer, elevated to the presidency. But he too faces losing his mandate if Brazil's top electoral court finds Ms Rousseff's 2014 re-election campaign was illegally financed with money stolen from Petrobras.
Such an outcome would only deepen the crisis that has paralysed the political class, leaving it unable to tackle the recession as the two men next in line for the presidency, the heads of the lower house of congress and the senate respectively, are deeply tainted by corruption and face charges for involvement in the Petrobras scandal.
Anti-government protesters will also take to the streets on Saturday in neighbouring Venezuela as part of a campaign launched by the opposition to remove embattled President Nicolás Maduro from office.
After its crushing victory over the ruling socialist party in December’s mid-term election the main opposition alliance says it will now gather up the signatures necessary to force a recall referendum later this year to end 17 years in power for the movement founded by the late president Hugo Chávez.
Mr Maduro has vowed his opponents “will not get rid of me”.