Intro:

Police attempt to disperse protesters by firing tear gas as metro strike continues in Sao Paulo on Monday.

Script:

Brazilian police and striking subway workers clashed in a central commuter station in the early hours on Monday morning, with union officials threatening to maintain the work stoppage through the World Cup opening match this week.

Riot police pushed about 100 striking workers out of the station, using tear gas to disperse the crowd from the streets outside, as the strike threw Sao Paulo's normally congested traffic into chaos for a fifth day.

The subway is the main means of transportation for World Cup fans scheduled to attend Thursday's opening match when Brazil face Croatia.

The stadium is about 20 kilometres (12 miles) east of central Sao Paulo, where most tourists will be staying.

About half of the city's subway stations were operating, but with greatly diminished service.

One union leader said the strike would continue through the tournament opener unless the government met workers' demands for a pay increase of just over 12 percent.

The striking workers later 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.

The stand-off with the Sao Paulo transport workers is the latest unrest to hit Brazil in the run-up to the World Cup.

The work stoppages are in addition to a steady flow 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 woeful public services like hospitals, schools, security and transportation.