Sao Paulo subway workers on strike over wages were met with riot police who used tear gas on them Monday, just three days before the 2014 FIFA World Cup is set to debut in the Brazilian city.

Although a court ordered the workers to return to their jobs, the workers haven’t abided by the decision. Instead, they voted to continue a strike “indefinitely” on Sunday, and the protests threaten to disrupt the World Cup, which kicks off Thursday in Sao Paulo when hosts Brazil take on Croatia. If the strikes linger through Thursday, thousands of fans will have to access Arena Corinthians Stadium without public transportation -- just one of the nightmare scenarios at the World Cup.

About 300 workers were protesting as they demanded a 12.2 percent salary increase, according to BBC. A similar strike on Saturday disrupted the commutes of millions of people in Sao Paulo even as Brazil competed in a World Cup warm-up match against Serbia, Sky News reported.

And it's not just Sao Paulo that has been the site of protests. Demonstrations led by bus drivers, teachers and police, who are demanding better pay, have gripped other Brazilian cities.

Brazilian President Dilma Roussef has said she won't allow violent protests be a distraction to the World Cup.

“Our problem is not with the national team,” union leader Paulo Pereira da Silva told Sky News. “We will cheer for them. But on October 5 [the date of Brazil’s presidential election], we will send Dilma Roussef to hell.”