Brazilian media are reporting that the country's top prosecutor has asked the Supreme Court to open an investigation into alleged obstruction of justice by embattled President Dilma Rousseff.
Officials have not confirmed the reports, which surfaced late Tuesday. Brazil's Globo News reported Rousseff is suspected of trying to obstruct an investigation into state-owned Petrobras oil company.
Brazilian newspapers quoted chief prosecutor Rodrigo Janot as saying he has requested authority to investigate Rousseff and also her predecessor and ally, Luiz Inacio Lula da Silva. The investigation is reported to be centered on wiretapped phone calls between the two.
Rousseff is already under investigation for a separate issue and could face an impeachment trial as early as next week. She is accused of covering up budget shortfalls in 2014 to improve her chance of reelection. Rousseff denies the accusations.
She has also said launching an impeachment process will harm the nation's political stability.
The lower house of parliament has already voted to start the impeachment process, and the Senate is expected to vote on the matter within days. A simple majority of the Senate could suspend her and start a trial that could last up to six months. If found guilty, Rousseff will be the first Brazilian leader to be impeached in more than 20 years.
Rousseff's possible impeachment has dominated Brazilian media while the country strives to revive its economy from its worst recession in decades, fight the Zika virus epidemic, and prepare for the 2016 Olympic Games set to be held in Rio in less than four months.