SAO PAULO -- Police confronted striking metro workers in Sao Paulo early on Monday in a central commuter station, with union officials threatening to maintain the picket beyond Thursday's World Cup curtain-raiser in the city.
Authorities are deeply worried about the strike because the subway is the main means of transportation to the Arena Corinthians -- located 12 miles east of the city centre -- where Brazil face Croatia in the tournament's opening match.
Riot police firing tear gas pushed around 100 striking workers out of Ana Rosa station as the strike threw Sao Paulo's normally congested traffic into further chaos for a fifth day. About half of the city's subway stations were operating, but with greatly diminished service.
"This is the way they negotiate, with tear gas and repression," said Alexandre Roland, a union leader, as he and others regrouped outside the station after confronting riot police.
The striking workers marched toward the city centre, where they planned to join a wide-ranging rally by various activist groups, including homeless workers demanding low-cost housing and a group calling for free public transportation.
Roland said the strike will continue through the tournament opener unless the government meets workers' demands for a pay increase of just over 12 percent.
A Sao Paulo labor court over the weekend fined the union $175,000 for the first four days of the strike and said it would add $220,000 for each additional day the work stoppage continued.
So far, the government-controlled company that runs the metro is offering an eight percent increase, and says it cannot go higher because fares haven't been raised for two years. Last year, a fare increase was reversed after violent protests broke out.
The standoff with the Sao Paulo transport workers is the latest unrest to hit Brazil in the run-up to the World Cup. Teachers remain on strike in Rio de Janeiro and routinely rally and block streets and police in several cities have also gone on strike, though they're back at work now.
The work stoppages are in addition to a steady drumbeat of anti-government protests that began a year ago during massive rallies in scores of Brazilian cities.
Those protests blasted government spending for the World Cup and demanded big improvements in public services like hospitals, schools, security and transportation. The protests have greatly diminished in size but not in frequency.
Demonstrations have repeatedly erupted in Brazil's metro areas in recent months, with even a small number of protesters blocking main roadways and severely disrupting traffic.