Sao Paulo, Brazil (BBN)-Brazilian riot police have used tear gas against protesters in Sao Paulo, three days before the World Cup opening game in the city's main stadium.
The BBC's Katy Watson at the scene says about 300 demonstrators are there and helicopters are circling overhead.
The protest was called by Sao Paulo metro workers who are striking in support of a 12.2 percent salary increase, reports BBC.
Brazilian President Dilma Rousseff has said she would not allow violent demonstrations to mar the World Cup.
Sao Paulo metro workers have been on strike since Thursday, creating traffic chaos in one of the world's most congested cities.
On Sunday, union members voted to continue to strike indefinitely despite a court order for them to return to work and a threat of dismissal by the state governor.
If the strike runs on until Thursday, it could affect the opening match between hosts Brazil and Croatia.
Arena Corinthians stadium is on the outskirts of Sao Paulo and access to the venue without public transport could be a huge challenge for fans.
BBN/ANS-09June14-6:00pm (BST)