Fifa president Sepp Blatter expressed sorrow on Wednesday after a fatal accident at the stadium that will stage next year's opening World Cup match in Brazil.
Three deaths were reported in Sao Paulo where structural damage at the Arena Corinthians saw part of a roof fall away to the ground. A crane was also felled and damage was caused to another stand.
Pictures shown in Brazilian media, including the website of newspaper Estadao, showed the mangled metal work of the roof and crane on the ground, and a large crack in the adjacent stand.
Estadao initially quoted a police officer, Mauro Lopes, as saying it was believed there were three fatalities, however subsequent reports have indicated there may have been two deaths.
A source at the Local Organising Committee confirmed there had been fatalities but would not initially be drawn on the number, nor on the implications of the collapse, or its cause.
Fifa president Sepp Blatter said on Twitter: “I’m deeply saddened by the tragic death of workers Corinthians arena today. Our heartfelt condolences are with the families.”
Hosts Brazil are due to play in the opening match at the stadium on June 12th, 2014, against opponents to be determined at next month’s draw.
The stadium is also due to stage five further matches, including a semi-final.
Fifa general secretary Jerome Valcke added on Twitter: “Extremely shocked by the news from Sao Paulo. Our thoughts are with the families of the victims of this accident.
“We are currently awaiting further details from the authorities, who are investigating this tragic accident.”
Fifa said: “Fifa and the LOC have learnt of the death of workers at the Corinthian’s Arena site in Sao Paulo with great sadness. We wish to send our heartfelt condolences to the family of the workers who tragically died today.
“The safety of workers is the top priority for Fifa, the LOC, the federal government. We know the safety of all workers has always been paramount for all the construction companies contracted to build the 12 Fifa World Cup stadiums. The local authorities will fully investigate the reasons behind such a tragic accident.”
Corinthians, the club that will move into the stadium, issued a short statement on their website that said: “The board of Sport Club Corinthians Paulista deeply regrets the accident earlier in Corinthians Arena.
“(There is) no other information at this time.”
A second statement from the club added: “Because of the incident that occurred in work at Arena Coninthians on Wednesday afternoon, Sport Club Corinthians Paulista decreed seven days of mourning.”
The LOC said the deadly accident would be the subject of a full investigation.
It added that all parties involved in preparations for the World Cup were dedicated to ensuring high standards in workers’ conditions.
The LOC statement said: “Fifa and the LOC have learnt of the death of workers at the Corinthians Arena site in Sao Paulo with great sadness. We wish to send our heartfelt condolences to the family of the workers who tragically died today.
“The safety of workers is the top priority for Fifa, the LOC, the federal government.
“We know the safety of all workers has always been paramount for all the construction companies contracted to build the 12 Fifa World Cup stadiums. The local authorities will fully investigate the reasons behind such a tragic accident.”
The construction firm building the new stadium, Odebrecht, reported earlier this month that the World Cup venue was 94 per cent finished.
It said on its website that 1,500 workers were involved, with the focus turning to the final details of the project.
The final part of the stadium roof, covering the north stand, was being installed on Wednesday when the tragedy occurred.
