RIO DE JANEIRO - More than half a million Brazilians poured into the streets of at least 80 Brazilian cities Thursday in demonstrations that saw violent clashes and renewed calls for an end to government corruption and demands for better public services.

A man, with a Brazilian national flag laid out in front of him, shouts during a protest demanding improvements be made to the public transport system, at the bus station in the centre of Brasilia June 19, 2013. [Photo/Agencies]

Riot police battled protesters in at least five cities, with some of the most intense clashes happening in Rio de Janeiro, where an estimated 300,000 demonstrators swarmed into the seaside city's central area. Television images showed police firing tear gas canisters and rubber bullets into crowds of young men, their faces wrapped in T-shirts. Other demonstrators were shown detained lying on sidewalks.

In Brasilia, police struggled to keep hundreds of protesters from invading the Foreign Ministry, outside of which protesters lit a small fire. Other government buildings were attacked around the capital's central esplanade. There, too, police resorted to tear gas and rubber bullets in attempts to scatter the crowds.

Clashes were also reported in the Amazon jungle city of Belem, in Porto Alegre in the south, in the university town Campinas north of Sao Paulo and in the northeastern Brazilian city of Salvador.

"This was meant to be a peaceful demonstration and it is," said artist Wanderlei Costa, 33, in Brasilia. "It's a shame some people cause trouble when there is a much bigger message behind this movement. Brazil needs to change, not only on the government level, but also on the grass roots level. We have to learn to demonstrate without violence."

The protests took place one week after a violent police crackdown on a much smaller protests in Sao Paulo galvanized Brazilians to take to the streets.

The unrest is hitting the nation as it hosts the Confederations Cup football tournament with tens of thousands of foreign visitors in attendance. It also comes one month before Pope Francis is scheduled to visit the nation, and ahead of the 2014 World Cup and 2016 Olympics, raising concerns about how Brazilian officials will provide security.