The Marseille hospital authority says a second person has died after the roof of a stage being built for a Madonna concert collapsed.

The hospital authority says the British worker died Friday from injuries suffered in the accident.

A French worker was killed immediately when the roof fell apart on top of several workers Thursday.

Eight others were injured, including an American who is in serious condition.

None of the victims' identities has been released.

Madonna canceled her scheduled performance Sunday in this Mediterranean port city after the accident.

The cause of the roof collapse was not clear. Police say a faulty power winch may have played a role.

Di Nocera said the roof had been about two-thirds complete when it collapsed gradually on top of several workers.

"Since it did not collapse right away, that allowed several people to get out, to avoid being hit," he said.

Madonna's Sticky & Sweet" tour was due to arrive in Marseille on Sunday, but the concert was canceled because "rebuilding a stage, it's not possible," Di Nocera said.

Marseille prosecutors asked the regional safety agency to investigate the cause of the accident.