A crane collapsed on Wednesday at the construction site of a future World Cup soccer stadium in Sao Paulo, Brazil, killing at least three people and apparently causing damage to the structure.

The stadium, which was scheduled to be finished in the next month or so, is to be the site of the opening game and five other matches when Brazil hosts the 2014 soccer World Cup in June and July.

A spokeswoman for the Sao Paulo state military police confirmed the deaths.

Brazil has struggled to deliver stadiums, public transportation improvements and other World Cup-related projects within the timelines specified by world soccer body FIFA. Some construction sites, such as a new terminal at Sao Paulo's international airport, are being built around the clock seven days a week to try to finish them before the Cup.

The Sao Paulo stadium, formally called Arena Corinthians but known locally as "Itaquerão," is being built by Brazilian industrial conglomerate Odebrecht SA, which recently said the arena was 94 percent complete.

Photos taken by local media appeared to show significant damage caused by the fallen crane to the outside of the stadium. It was not immediately clear if the damage could pose a major delay to opening the stadium.

A spokeswoman for Odebrecht declined immediate comment. Corinthians, the Sao Paulo soccer club that will play in the stadium after the Cup tournament, lamented the accident in a short statement but declined further comment.