A top Brazilian prosecutor says general elections in 2018 will be the climax of the country's biggest ever corruption probe, known as Operation Lava Jato ("Car Wash").
"2018 will be the final battle of Lava Jato, because the 2018 elections will determine the future of the fight against corruption in our country," said Deltan Dallagnol, a central prosecutor in the probe, during a conference in Rio de Janeiro.
The presidency and Congress are up for election in October next year, the first major polls since the Lava Jato probe plunged Brazil into political crisis.
The giant corruption investigation was launched in early 2014, uncovering a vast web of embezzlement and bribery through the Brazilian government, legislature and corporate world, especially the state oil company Petrobras.
Former president Luiz Inácio Lula da Silva has been convicted of bribe-taking and current President Michel Temer is charged with racketeering and bribe-taking. Dozens of lawmakers also face charges or probes.
Although the anti-corruption campaign has been popular with Brazilian voters, lawmakers led by Temer have repeatedly pushed back against prosecutors, arguing that they are on a politicised crusade and have exceeded their authority.
In a joint statement, prosecutors from Rio, Sao Paulo and Curitiba states warned at the conference that "attempts to guarantee impunity for powerful politicians are intensifying."
"It's essential in 2018 that every voter acts carefully (voting for) deputies and senators with a clean sheet and committed to democratic and republican values, and who support the anticorruption agenda," the statement said.
The next batch of congressional deputies and senators "will determine whether there is a retreat in the fight against corruption or if there will be reforms and advances that create a fairer country," Dallagnol said.
The Lava Jato team said that it has so far opened 416 criminal cases and secured sentences against 144 people, totalling 2,130 years prison.
Another prosecutor, Eduardo El Hage, warned that there would be new operations next year.
"We are planning concrete actions," he said. "It will be a year of a lot of work."