RIO DE JANEIRO - Police fired tear gas to break up hundreds of protesters outside Rio de Janeiro's Maracana Stadium where Colombia and Uruguay played a World Cup knockout stage match.
About 350 anti-World Cup protesters marched toward the Maracana closely guarded by about 250 police, who fired tear gas to disperse them just as they came within sight of the stadium.
An AFP correspondent saw police detain at least three demonstrators and frog march them away from the crowd.
Mass protests erupted just over a year ago in Brazil, at first drawing hundreds of thousands of people into the streets to condemn the record $US11 billion ($A11.90 billion) spent on the World Cup and shoddy schools, hospitals and public transport.
But recent demonstrations have been far smaller, with many Brazilians more interested in football or frightened by the violent tactics of hardcore protesters such as the anarchist Black Bloc movement.
Police charged a group of protesters wearing the Black Bloc's trademark black masks, breaking the demonstration into several smaller groups.
A police motorcycle unit backed by some 30 police cars then chased the main group back to their starting point, about a kilometre from the stadium.
Demonstrators chanted "Fascists!" at riot police as they cracked down on the protest.
"This isn't going to end with the World Cup."