Brazil is holding three days of national mourning for the two construction workers killed at a World Cup stadium that will now be completed up to two months late.

The pair died when a crane at the Corinthians Arena in Sao Paulo collapsed as it was hoisting a 500-tonne structure.

It damaged the outer walls of the 70,000-seater venue – popularly known as the Itaquerao – and a giant LED screen.

Work on the stadium, which is due to stage the opening World Cup fixture, was due to be finished by December 31.

The competition’s organisers Fifa say they expect a delay of between 45 and 60 days.

Fifa, football’s world governing body, had originally set December 31 as the deadline for the completion of all the stadiums for next summer’s tournament.

The latest delay will increase worries over whether Brazil will be fully prepared for the June 12 kick-off.

Six venues have already been declared ready but there are concerns about three others in Cuiaba, Manaus and Curitiba.

Bosses at the Corinthians Arena said the “structure of the grandstand was not compromised” by the crane accident and that work will resume on Monday.

Andres Sanchez, operations director, said the two construction workers were crushed to death.

They have been named as Ronaldo Oliveira dos Santos, 44, a fitter, and driver Fabio Luiz Pereira, 42, who was inside his truck when it was hit by the falling structure.

Most of the 1,700 workers at the site were on lunch break when the crane toppled over.

In a statement, Corinthians said it was the 38th time the crane had performed the procedure and that a similar structure had been successfully installed a week ago.

The crane, which has a reach of 114 metres, can lift up to 1,500 tonnes.

Investigators are looking into the reason for the collapse.

Fifa said the safety of workers was a “top priority”, while the organisation’s president, Sepp Blatter, said he was “deeply saddened by the tragic death of workers”.

The incident is by no means the first to hit Brazil’s World Cup preparations. One worker died last year during construction of a stadium in the capital, Brasilia, and another was killed at the Manaus stadium last March.

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