(CNN) -- A construction accident at the site of the Brazilian stadium that will host the opening match of the World Cup killed two workers, Sao Paulo fire officials said Wednesday.
Officials initially said there were three victims, but the fire department amended the death toll on its Twitter account.
The Arena Corinthians is one of the venues that will host World Cup matches in 2014.
A crane was hoisting a part of the metal roof when it collapsed, causing the piece to fall, partially damaging the building, according to a statement released by the construction company, Odebrecht Infrastructure.
It was a procedure that had been carried out many times at the construction site without incident, including the installation a week ago of a piece of roof of the same proportions, the company said.
The stadium is to be the home of Sport Club Corinthians Paulista. The club's directors issued a statement expressing sadness over the incident.
The construction company identified the victims as Fabio Luiz Pereira, 42, and Ronaldo Oliveira dos Santos, 44.
The accident comes as Brazil faces an approaching deadline to finish construction on its World Cup stadiums.
Earlier this year, FIFA Secretary General Jerome Valcke declared that all stadiums would have to be ready by December. The tournament is to be held from June 12 to July 13.
In August, Brazil's sports minister, Aldo Rebelo, relayed concerns over delays at five of the stadiums being built.
It was unknown how much Wednesday's incident would affect the construction of the Arena Corinthians.
The state-run Agencia Brasil news agency reported that about a third of the stadium will be closed off as officials investigate the accident. Workers were excused for several days of mourning.
"We are less concerned with timelines," Andres Sanchez, the former president of Corinthians, told reporters, according to Agencia Brasil. "We are concerned about satisfying you and attending to the victims' families."
Brazil suffered a setback last month when a judge ordered the suspension of construction at another host venue due to safety concerns.
The judge stopped work at the Arena de Baixada, in the city of Curitiba, over concerns that workers were in danger of "being buried, run over, falling from heights and being hit by material, among other serious risks."
Preparations for the World Cup have been controversial in Brazil.
Protesters are outraged at what they consider lavish spending on the World Cup as well as the 2016 Olympic Games.
They have also been critical of the lack of investment in public services, schools, hospitals and transportation. That led thousands to march earlier this year on the streets across the country.
CNN's Shasta Darlington, Miguel Castro, James Masters and John Sinnott contributed to this report.