President Dilma Rousseff has announced a series of anti-graft measures following Sunday's massive nationwide rallies that protested rampant corruption in Latin America's largest country and called for her impeachment.

In a speech aired nationwide, Rousseff said Wednesday "we have the duty and obligation to fight impunity and corruption."

Among the measures announced are the criminalization of slush funds used to finance election campaigns, the seizure of assets of people found guilty of corruption, and the requirement that government officials must have a clean criminal record.

"This is a decisive step to expand the government's capacity and power to prevent and combat corruption and impunity," Rousseff said.

Sunday's protest marches were sparked by anger over a sprawling corruption case involving Petrobras, Brazil's state-owned oil company.