SAO PAULO: Police clashed with striking subway workers in Sao Paulo on Friday as traffic chaos gripped the Brazilian mega-city less than a week before it hosts the World Cup’s opening game.

Police fired tear gas and swung batons to beat back the picketing strikers after commuters tried to enter a major metro station amid torrential rain that has added to the traffic misery.

The indefinite work stoppage, now in its second day, has raised fears of unrest when the country’s business hub hosts next Thursday’s game between Brazil and Croatia.

The clashes came as Brazil’s national team prepared to play their last friendly on Friday night against Serbia in Sao Paulo’s Morumbi stadium, not the new Corinthians Arena, which has yet to be finished six days from the inaugural match.

The Sao Paulo metro is the main link to the Corinthians Arena, and the strike could force organizers to come up with last-minute alternative transportation for tens of thousands of fans.

The traffic mayhem has stranded the 4.5 million passengers who use the subway system daily in the sprawling city, while bumper-to-bumper traffic stretched for up to 250 kilometers (155 miles).

FIFA is “not afraid” things will go wrong at the start of the World Cup despite preparation problems in Brazil.

Football’s governing body said Thursday it’s “in control” of what needs to be done to get the tournament off to a good start in a week.

“The general feeling is that we have done … all we need in order to ensure that the World Cup will start on the 12th of June,” Secretary General Jerome Valcke said after a meeting of the local World Cup organizing committee.

The meeting took place the day Sao Paulo was thrown into transit chaos as subway and overland commuter train operators went on strike, putting at risk the only means that most football fans will have to reach the Itaquerao stadium which will host the opener between Brazil and Croatia on June 12.

“We are in control, we are not afraid of the next days,” Valcke said, noting that he was confident local authorities would do everything possible to keep events such as strikes and protests from “impacting” the tournament.

Asked if the country was ready, Brazil Sports Minister Aldo Rebelo admitted there were some preparation problems and said it was impossible “to hang a diploma on the wall saying everything is ready.” “We know of our difficulties,” he said. “We have done everything that was within our reach … to give visitors a warm welcome.” After local organizers presented their latest report on the country’s preparations, President Sepp Blatter said FIFA was “confident” the tournament will be successful.

Blatter and FIFA again refused to directly address the equally troubled 2022 World Cup in Qatar, which came into question after a report by the Sunday Times in Britain alleged that Mohammed Bin Hammam, who FIFA expelled in 2012, paid football officials millions of dollars to support the nation’s successful campaign.

FIFA communications director Walter De Gregorio started Thursday’s news conference by stressing that “we can’t say anything about this” until FIFA prosecutor Michael Garcia wraps up his investigation.

“The only thing I can say to the Qataris is that … we do not put the World Cup in Qatar into question,” Blatter said. “We are waiting for the result of the investigation.” Valcke said it’s normal there’s still work to be done in some of the stadiums, including the addition of seats and the installation of generators. The secretary general downplayed the unfinished work at the Itaquerao.

“It’s true that if you go to Itaquera it looks like around the stadium there’s quite a lot of work still going on,” Valcke said. “But I would say it’s quite normal, and it’s even more normal when some of the stadiums were late.” The first time the Itaquerao will host a match with a capacity crowd will be the opener. FIFA usually plans three test events in each of the venues, but that wasn’t possible in Sao Paulo because of the delays, including one caused by the collapse of a huge crane late last year.

Brazil promised to finish all 12 stadiums by the end of last year as required by FIFA, but six venues missed that deadline. Half of the stadiums were ready for last year’s Confederations Cup, although several deadlines were also missed then.

Although Brazil had seven years to prepare for the World Cup, it arrives on the eve of the tournament knowing that many of the infrastructure projects promised by the government will not be ready.

FIFA said it received an “unprecedented number” of nearly 11 million ticket requests for the tournament in Brazil. It sold a total of about 2.9 million tickets, including more than 2.2 million directly via FIFA.com to the general public. Overall, 60 percent of the tickets went to Brazilians. Americans were the second-biggest buyers, with almost 197,000.

“Never before have we sold so many tickets directly to the general public,” Valcke said.

FIFA also said it’s launching a social media campaign “inviting people around the world to unite against racism” by posting messages with the saynotoracism hashtag.

Blatter said the “Say No to Racism” campaign “is our commitment to drive racism from the game and to set an example of equality for all to society.”