A worker died Saturday after falling at the construction site of the stadium that will host the World Cup opener in Sao Paulo, marking the seventh death in accidents at World Cup venues in Brazil.

Fabio Hamilton da Cruz, whose age was not disclosed, fell about 26 feet (8 meters) while helping install temporary seats at the Itaquerao stadium, construction company Fast Engenharia said in a statement. Firefighters said the worker fell from about 50 feet (15 meters).

The press office of the Hospital Santa Marcelina in Sao Paulo confirmed the death, saying the worker didn't survive serious head injuries. He was pronounced dead just before he was expected to undergo surgery.

Details on the accident were not immediately released, but Fast Engenharia said the worker was wearing all the required safety equipment at the time of the fall.

Brazil's sports minister, Aldo Rebelo, released a statement lamenting the death and saying officials were awaiting results from an investigation into what happened.

FIFA Secretary General Jerome Valcke said on his Twitter account that he was "deeply saddened by the tragic loss of a worker."

FIFA and the local World Cup organizing committee said in a statement that they were waiting for the official report on the death.

"For FIFA, the LOC and the Brazilian authorities safety is paramount," the statement said.

The accident comes about four months after two workers died when a crane collapsed at the stadium while hoisting a 500-ton piece of roofing.

It was the eighth death at World Cup venues so far, the seventh in accidents. Three workers died in the Arena da Amazonia in the jungle city of Manaus, including a 55-year-old Portuguese man killed while disassembling a crane that was used to install the stadium's roof earlier this year. Another worker there died of a heart attack.

In 2012, a worker died at the construction site of the stadium in the nation's capital, Brasilia.

Construction was already behind schedule in Sao Paulo because of the damage caused by the earlier accident in late November, when the roofing structure fell on part of the stadium's facade.

FIFA said it was expecting the venue to be finished in mid-May, about a month before the June 12 opener, but it wasn't clear if Saturday's incident would prompt further delays.

About 20,000 temporary seats were being added to the new stadium to increase its capacity for the high-profile inaugural match between host Brazil and Croatia.

Construction at Brazil stadiums has been plagued by delays and three venues remain unfinished less than three months before the opener. The other two stadiums under construction are the Arena Pantanal, in the city of Cuiaba, and the Arena da Baixada, in the southern city of Curitiba.

Brazil promised that all 12 stadiums would be ready by the end of last year but only six were completed by then -- the ones used in last year's Confederations Cup, a World Cup warm-up tournament.

Infrastructure work across Brazil also remains far from completed, but authorities insist the country will be ready to host its first World Cup since 1950.