Subway workers late on Monday suspended a strike that crippled traffic in Brazil's biggest city, but warned they could resume their walkout on Thursday, when Sao Paulo hosts the first game of the 2014 soccer World Cup.

Fans arriving in the city earlier Monday were met by daunting traffic jams and other delays after police used tear gas to disperse the striking workers. It was the fifth day of salary protests. Union leaders and local authorities are to renew negotiations on Wednesday.

In a separate incident Monday, a construction worker helping to build a new monorail — a project meant to expand the city's outdated transit network before Brazil hosts the 2016 Olympic Games — was killed after a large concrete support beam fell while it was being erected. 

Originally, the expansion of the metro system was meant to be completed before the World Cup to help fans move around the congested city. But in 2011, just a year after construction began, the government already warned it wouldn't be ready in time for the Cup.

'It'll be chaos'

The metro walk-out added to widespread concerns over whether Brazil's government can prevent street protests and other simmering labour disputes from disrupting the World Cup, which starts on Thursday when Brazil and Croatia face off at a controversial new stadium on Sao Paulo's long-neglected east side.

The strike caused giant traffic jams again on Monday, creating huge delays for soccer fans trying to get into the city.

World Cup 2014: Sao Paulo

Street artist Paulo Ito, angry over FIFA's control of World Cup, painted this mural in Sao Paulo. It is one of dozens created by artists in one day on the exterior of a school wall. (Susan Ormiston/CBC)

Many waited for around two hours in lines for taxis at the city's international airport and spent another two or three hours to reach their hotels.

"If this continues, it'll be chaos," said Miguel Jimenez, a fan from Mexico.

Sao Paulo, also Brazil's business hub, will host five matches after the opener, including a semi-final.

Brazil has drawn criticism at home and abroad for failing to complete key infrastructure projects on time. It is expected to put on a good World Cup, but many Brazilians are angry over how much was spent and how the country still struggled to be ready.

"We've known this was going to happen for years, but nobody solved these problems," said Ricardo Fars, a Brazilian manager for a technology company who returned to Sao Paulo from a business trip in Peru on Monday and waited at least two hours for a taxi.

Police clash with protesters

Police fired tear gas at metro workers at the city's Ana Rosa station on Monday morning, and the state metro company later said it had fired 42 striking workers. Union officials late on Monday said the success of continued negotiations, and any decision to resume the strike, would hinge on whether the dismissed workers are rehired.

A local court ruled on Sunday that the strike was illegal. Workers are pushing for a 12 per cent pay rise, well above the company's offer of 8.7 per cent.

Other groups, including teachers and bus drivers, have staged strikes in Sao Paulo in recent weeks to demand higher

World Cup 2014 Sao Paulo strike

The transit strike last nearly five days before it was suspended Monday. On the weekend, a Brazilian judge ruled the strike illegal, but if workers decide to walk off the job again later this week, fans trying to make it to World Cup matches could be left without a hope: already, fans are waiting two hours or more for a taxi. (Chico Ferreira/Reuters)

pay. Analysts say the city is becoming a battlefield for dissenting political views, hurting its economy and creating a climate of unease ahead of the World Cup.

Frustration with broken promises and the ballooning cost of new World Cup stadiums contributed to widespread protests that drew over a million Brazilians into the streets during a soccer tournament last year.

World Cup organizers got a boost on Monday, however, when the homeless worker's movement, which has organized most of the protests of recent weeks, said it had reached an agreement with the government and would not take to the streets during the tournament.

In a statement, Brazil's government late Monday said it had agreed to build public housing units near the stadium as one of several concessions to the group.

With files from The Associated Press