A construction worker at Sao Paulo's troubled World Cup stadium was killed after falling from a stand on Saturday, bringing the number of deaths at the venue to three.
The workman, named as Fabio Hamilton da Cruz, fell eight metres (26 feet) as he helped install temporary seating at the ground and was taken to hospital where his condition had been described as serious.
His employers said in a statement that he was observing all the necessary safety standards at the ground which will host the opening game of the World Cup between hosts Brazil and Croatia on June 12.
In November, two men died when a crane collapsed at the same arena.
The Sao Paulo stadium was one of six venues to miss an initial FIFA delivery deadline of December 31 and is only set to be handed over to organisers in mid-May.
A total of seven workers have now been killed during work on Brazil's 12 World Cup venues.
In a statement, sports minister Aldo Rebelo expressed his "profound regret" at the news of da Cruz's death and added that an investigation would be immediately launched.
Saturday's tragedy came just two days after FIFA secretary general Jerome Valcke had admitted progress on the Sao Paulo stadium remained a concern with the problems compounded by arguments over who foots the bill for temporary facilities.
But Valcke added: "We will have 12 host cities; we will have 12 stadiums....but there is work to do. Time is flying."
Rebelo insisted the authorities were lending their full support.
"We are helping so that the town hall, the state government and the (private) owners of Corinthians Arena find a solution," Rebelo said.
Earlier this week, Brazil's Development Bank released the first two-thirds of a $160 million loan to complete the stadium project.
But confusion remains over who finances some $20 million in 'overlay' or temporary facilities.
Despite the tight timetable, Valcke said on the basis of talks with constructor Odebrecht he was confident of progress.
"I have full trust in Odebrecht to deliver on time for the opening game," said Valcke.
However, initial agreements for the host cities do not make Odebrecht responsible for the cost of the work but rather the owner, club side Corinthians.
Valcke said come what may, with 75 days to go until the first match Sao Paulo would definitely stage the curtain-raiser.
"It will happen in Sao Paulo. There is no other choice. It was a decision we made with the LOC and government to keep these 12 cities whatever will be the challenges.
"It will happen in Sao Paulo -- there is no other choice" even if "we will maybe be a bit borderline."