Brazil's federal police were serving 27 additional arrest warrants on Friday in a broad money-laundering investigation that has ensnared a former senior executive at oil firm Petrobras, causing it to delay releasing its results.

The police said in a statement 300 officers were involved in the operation in five different states and the capital district. Several warrants were being served at "large companies," the statement said, without identifying companies' names or the individuals targeted.

The move comes a day after Petroleo Brasileiro SA, as the state-run oil company is formally known, delayed the release of its third quarter earnings report, saying it needed time to investigate allegations of corruption.

The money-laundering probe, known as "Operation Car Wash," was first launched in March as police investigated an alleged money laundering scheme involving Petrobras.

The continuing fallout of the scandal has put pressure on leftist President Dilma Rousseff, who won a narrow re-election last month.

A former Petrobras executive jailed in the case has said in a plea bargain deal that kickbacks from contracts were funneled to Rousseff's Worker's Party and its allies in Congress.