An opera house which controversially dropped a Mozart production featuring the severed head of Muhammad over security fears has suffered an embarrassing setback shortly before the disputed show resumes — it has lost the offending prop.

The head of the Prophet as well as those of Jesus, Buddha and Neptune feature in the closing scene of a modified version of Mozart's "Idomeneo" that Berlin's Deutsche Oper pulled from its November program out of concern that it could draw Muslim anger.

After a hail of criticism and an all-clear from police, the opera house rescheduled two performances of the show for Dec. 18 and Dec. 29.

However, opera spokesman Alexander Busche on Friday on Friday confirmed a report in the Berliner Morgenpost newspaper that the four heads had gone missing.

"We can't find the heads at the moment, but that doesn't mean they have been stolen. We don't think that's the case," Busche said. "Either they will show up in the next few days, or we will have new ones made."

"What we can say is that, on the 18th, the work will be performed on stage with all the necessary props," he said.

Deutsche Oper head Kirsten Harms had canceled Hans Neuenfels' interpretation of Idomeneo following a vague security warning from police.

The decision provoked widespread debate in the wake of Pope Benedict XVI's controversial remarks about Islam and the international uproar over a Danish paper's publication of unflattering caricatures depicting Muhammad.

Neuenfels has refused to have the scene cut from his interpretation of the 225-year-old opera, saying it represented his protest against all organized religion. It's not part of Mozart's original work.

However, the opera company announced last month that it was returning the work to its winter lineup after a new police assessment found that no "concrete danger" existed.

Busche declined to comment on security arrangements for the December performances.

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