French Transport Ministry announced Tuesday that the collapse of part of a roof at Paris's Charles de Gaulle airport terminal late last month was probably caused by perforation of the concrete vault.

"The main cause of the collapse is linked to perforation of theconcrete archway by (cylindrical metal struts)," the ministry saidin a statement based on a preliminary report by a committee of inquiry on the accident.

"It is probable that gradual deterioration of the condition of the concrete has prepared and led to this perforation," the statement said.

The collapse accident, on May 23 in the ultra-modern Terminal 2E at Paris' biggest airport, killed four people and injured threeothers

The perforation, whose origin is still impossible to define, caused the vault to split under pressure, according to the statement.

"A metal strut had gone through the concrete shell at a point where the crack occurred. In doing so, the strut was no longer able to support the structure, which then folded in on itself and collapsed", the statement said.

As long as the primary causes of the collapse have yet to be finally established, there are no plans to demolish the remains ofthe terminal, it added.

Reports here said French Transport Minister Gilles de Robien had asked for the investigation's first conclusion by the end of June.

Terminal 2E was opened last year at a cost of 750 million euros(900 million dollars) and had been handling around 20,000 passengers a day before it was closed after the incident.

The French authorities had said the building might have to be demolished if investigations showed that the accident was due to adesign fault.

Source: Xinhua