SAO PAULO, Nov 28: Part of the stadium that will host the 2014 World Cup opener collapsed on Wednesday, killing two workers and aggravating already urgent concerns Brazil won’t be ready for football’s signature tournament.

The accident at the Arena Corinthians, known locally as the Itaquerao, could hardly have come at a worse time — just a week ahead of the draw that will determine the tournament’s schedule and with the top names in football all descending on Brazil.

Preparations have been plagued by setbacks including cost overruns, stadium delays, accidents, labour strife and huge street protests in the run-up to the June tournament, once envisioned as a coming out party for South America’s largest nation, which is also scheduled to host the 2016 Olympics in Rio de Janeiro.

Already, public prosecutors and a workers union in Sao Paulo were demanding an investigation into conditions at the venue, saying work shouldn’t resume until authorities deem the stadium safe.

Construction workers had been racing to finish the stadium in Sao Paulo, Brazil’s biggest city, prior to a December deadline imposed by world football body FIFA.

Andres Sanchez, operations director at the Arena Corinthians site, said the workers, aged 44 and 42, were crushed to death when a crane hoisting a 500-ton metallic piece to the top of the roof collapsed.

He said the cause of the accident was still unclear, adding that any possible delay to construction was “the least of our worries.”

Sanchez said the accident did not cause structural damage to the stadium’s stands, which likely would have caused the most extensive delays to construction.

“I don’t want to know about FIFA right now; we are worried about the families of the victims,” said Sanchez, a former president of the Corinthians soccer club.

A third worker was rushed to hospital with injuries after the accident, which brought a shocked response from FIFA president Sepp Blatter and condolences from the Brazilian ministry of sport.

“I’m deeply saddened by the tragic death of workers @Corinthians arena today,” Blatter said on Twitter. “Our heartfelt condolences are with the families.”

Work on the site has been suspended for three days of mourning until next Monday, after which 30 percent of the site will be closed to assist the investigation.

Delays surrounding the World Cup have extended well beyond stadiums. Numerous public transportation projects have been cancelled or shelved, and workers have toiled 24 hours a day, seven days a week to finish a new terminal at Sao Paulo’s international airport on time.

Six stadiums were used in the Confederations Cup warm-up tournament in June, but several of them were delivered later than FIFA wanted. But Brazil is racing against time to deliver the other six, and there is particular concern that the stadiums in Cuiaba, Manaus and Curitiba may not be ready by the end of December.—Agencies