Thousands of anti-government demonstrators again took to streets in several Brazilian cities on Saturday after the President broke a long silence to promise reforms, but the protests were smaller than those of recent days and with only scattered reports of violence.

Police estimated about 20,000 demonstrators gathered in a central square in the city of Belo Horizonte, largely to denounce legislation that would limit the power of federal prosecutors to investigate crimes in a country where many are fed up with the high rate of robberies and killings. Many fear the law also would hinder attempts to jail corrupt politicians and other powerful figures.

Ms. Rousseff made a televised appearance on Friday backing the right to peaceful protest but sharply condemning violence, vandalism and looting.

She promised to be tougher on corruption and said she would meet peaceful protesters, Governors and the Mayors of big cities to create a plan to improve urban transportation and use oil royalties for investments in education. Much of the anger behind the protests has been aimed at bus fares, high taxes and poor public services such as schools and health care.

In the northeastern city of Salvador, where Brazil’s national football team was set to play Italy in a match for the Confederations Cup, some 5,000 protesters gathered about five km from the stadium, shouting demands for better schools and transportation and denouncing heavy spending on next year’s World Cup.

Brazil’s news media, which had blasted Ms. Rousseff for her lack of response, seemed largely unimpressed with her careful speech, but noted the difficult situation facing a government trying to understand a mass movement with no central leaders and a flood of demands.

With “no objective information about the nature of the organisation of the protests” wrote a columnist “Dilma resorted to an innocuous speech to cool down spirits.” At its height, some one million anti-government demonstrators took to the streets nationwide on Thursday night.

Social media and mass e-mails were buzzing with calls for a general strike next week. But Brazil’s two largest unions, the Central Workers Union and the Union Force, said they knew nothing about such an action, though they do support the protests. At the protest in Salvador, 32—year—old public worker Mariana Santos said that demonstrators would Rousseff and the rest of Brazil’s government accountable if they fail to keep their promises.

More In: World | International