RIO DE JANEIRO — Thousands of demonstrators took to the streets in dozens of cities across Brazil on Saturday and were dispersed violently by the police while mounting some of the most vigorous expressions of anger with governing institutions since an outburst of antigovernment demonstrations shook the political establishment in June.

Still, fewer people turned out in major cities on Saturday than in the earlier wave of mass protests. That broad flare-up of public ire has given way to an array of more fragmented movements, some of which have been struggling in the face of crackdowns by Brazilian security forces.

“This whole government only knows how to rob us,” said Naiana Vinuto, 25, a management student among the protesters in Rio de Janeiro, expressing anger about political corruption in different parts of Brazil’s vast public bureaucracy.

Police officers in riot gear faced off in Rio’s old center with hundreds of demonstrators, arresting at least 24 people. As in the other cities, the protests here were organized to challenge the military parades commemorating Brazil’s independence. People attending the parade, including children, suffered from tear-gas inhalation as the police tried to disperse the protests.