Ratings agency S&P have downgraded Brazil's credit rating to 'BB+' from 'BBB-', so called junk status, and said its outlook was negative.
Another prominent Brazilian politician is facing corruption charges over the bribery scandal at energy giant Petrobras.
Speaker of the lower house, Eduardo Cunha, denies the charges of corruption and money laundering.
Fernando Collor de Mello, who was Brazil's president from 1990 to 1992, has also been charged by prosecutors investigating Petrobras but the exact nature of the charges against Mr. de Mello are not yet clear.
Hundreds of thousands of people took to the streets of Brazil over the weekend to voice their dissatisfaction with President Dilma Rousseff and her government - many called for Ms. Rousseff to be impeached.
President Rousseff's approval rating
The attacks happened in three different municipalities of the Brazilian city on Thursday night - with police investigating if the shootings are connected to the deaths of two police officers in recent days according to Globo.