Brazilian President Jair Bolsonaro has officially dismissed his key aide in charge of dealings with congress, days after a newspaper linked him to a corruption scandal involving phony candidates and the misuse of campaign funds.

Government spokesman Otavio Rego Barros didn't say Monday what motivated the president's decision to fire aide Gustavo Bebianno, who has been a close ally of Bolsonaro. Bebianno has denied any wrongdoing.

The scandal has cast a shadow over the government's first weeks in power and is proving a distraction on the eve of the administration presenting sensitive legislation to congress. Lawmakers are set to receive this week an anti-crime bill and a proposal to overhaul Brazil's pension system, the government's flagship reform.

Bolsonaro ran his campaign on the promise that he will tackle corruption.