The senators of Brazil are debating whether to put President Dilma Rousseff, the first woman that became Brazilian president, on trial because of assertions that she illegally manipulated the budget to hide a growing deficit.
After the debate, majority had said that Rousseff should face an impeachment trial.
The said debate will be followed by a vote that could suspend Dilma for 180 days as the duration of the investigation.
A majority of senators say they will vote to have Dilma Rousseff suspended for 180 days and as the protesters knew about it they clash with the police.
The supporters of Rousseff chanted "Out with ilma", outside Congress, where a metal fence was erected to keep apart rival protests, about 6,000 backers of impeachment. The police used pepper spray to disperse the group of supporters but the supporters hurled flares back. One person was arrested for inciting violence.