RIO DE JANEIRO — Tensions are high on the eve of political protests planned around Brazil on Sunday by supporters of the governing Workers’ Party and those who want to see President Dilma Rousseff impeached.

Opposition groups hope the protests will draw millions onto the streets nationwide. But differences between the two sides have been sharpened by police actions earlier this month that saw Rousseff’s predecessor, Luiz Inacio Lula da Silva, spirited to a Sao Paulo police station to testify in a sprawling investigation of corruption at the state-run oil giant Petrobras.

Some Workers’ Party supporters are expected to stage their own counter-demonstrations on Sunday, setting up concerns by authorities over the possibility of violence.

Brazil is suffering its worst recession in decades, with new official statistics showing the economy shrank by almost 4 percent last year.

Rousseff saw her approval ratings dip into the single digits in the first year of her second term. She is battling impeachment proceedings over claims she used state-backed banks to plug holes in the budget.

She has not been implicated in the massive Petrobras corruption probe, which has already ensnared many of Brazil’s businessmen and politicians from across the political spectrum.