Pro-impeachment lawmakers chanted “Dilma Out” in the lower house of Brazil’s Congress on Friday, as it opened a raucous three-day debate on whether to impeach President Dilma Rousseff on charges of breaking budget laws.

Pro-government demonstrators took to the streets in several states amid fears of violence as the debate began. Major trade unions and landless peasant movements planned bigger, nationwide protests on Sunday, when the debate is set to culminate with a vote that Rousseff is widely expected to lose.

The government lost a last-ditch appeal on Thursday before the Supreme Court to halt the impeachment process, which could bring further instability or even chaos to Latin America’s largest economy after 13 years of rule by the leftist Workers’ Party.