Two people have been killed and another injured by the collapse of a crane on the site of a Sao Paulo stadium that will host the opening game of next year’s World Cup.

“The initial toll of three has been revised downward to two and one injured person was rushed to hospital,” a police spokesman told AFP.

Police said a crane fell on workers rushing to complete the Arena Corinthians stadium, where the opening World Cup match is to be held next June.

The world football’s governing body FIFA set a December 31 deadline for finishing the work.

The crane collapsed as it was lifting a 500-ton lattice structure to the top of the stands, bringing down three metal structures, Globo television reported.

Associated Press reported that there were no major structural damages to the stadium but declined to say how much the accident may affect the delivery.

“I don’t want to know about FIFA right now, we are worried about the families of the victims,” former Corinthians president Andres Sanchez told a news conference.

Sanchez said two people were confirmed dead and nobody else was injured. A fire department official had said earlier that three people had died.

One of the workers, 42-year-old Fabio Luis Pereira, was inside a truck that was hit by the metal structure. The other, 44-year-old Ronaldo Oliveira dos Santos, was resting in an area which was supposed to be isolated.

”Unfortunately nobody saw him and he himself knew that he was not supposed to be there,” Sanchez said. ”He was napping and unfortunately there wasn’t time for him to get out.”

The accident happened at lunchtime, so not many of the nearly 1,700 employees working on the venue were on site when the crane collapsed on top of the metal structure, causing the deadly domino effect.

The stadium is one of 12 World Cup venues and Brazil has been struggling to overhaul sagging infrastructure in time for the games.

The reported $11 billion cost of staging the event has aroused public protests.

Fifa secretary general Jerome Valcke expressed his shock in a tweet.

Extremely shocked by the news from Sao Paulo. Our thoughts are with the families of the victims of this accident. (1/2)

— Jérôme Valcke (@jeromevalcke) November 27, 2013

We are currently awaiting further details from the authorities, who are investigating this tragic accident. (2/2)

— Jérôme Valcke (@jeromevalcke) November 27, 2013

A Fifa statement also expressed condolences for the families of the workers and said it would be fully investigated.

“The safety of workers is the top priority for FIFA, the LOC and 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.”