SAO PAULO (AP) -- The head of Brazil's Petrobras vowed Monday to use a widening corruption scheme to improve governance at the state-run oil giant, in part through creation of a compliance department aimed at stamping out corruption.

In her first public remarks since the arrests of around two dozen people including a top company executive late last week, Graca Foster told a conference call with investors, "We want to turn this difficult moment into something better."

"Petrobras is a company that dreams to produce more and more oil and more and more transparency," Foster said. "We are going through a very difficult moment in the company, but we are convinced that we will have better management after we structure and implement all of these management improvement processes."

Authorities allege top company officials operated a kickback scheme on contracts involving several billion dollars, with the money eventually fed back to the governing Workers Party and other top parties for political campaigns. On Friday, police arrested Renato Duque, former director of services of Petrobras, for his alleged role in the scheme, along with the heads of several top construction firms.

Foster said the scandal has underscored the need for a compliance department, which she said has the board of directors' full support and would be made operational as soon as possible, but remains in the planning phase.

During Monday's call, company officials also said they would not release until Dec. 12 the third-quarter results initially scheduled to come out last week to allow more time for an internal investigation. They said they'll need to revise data in the results if the allegations prove true.

The Petrobras scandal has been playing out for months, with allegations centering on what police have heard from Alberto Youssef, a convicted black-market money dealer who said he laundered hundreds of millions in the scheme and that the governing party benefited from it.

Youssef is talking to police in exchange for a lighter sentence. He claims recently re-elected President Dilma Rousseff and former President Luiz Inacio Lula da Silva knew about the kickbacks, an allegation both leaders vehemently deny.