PARIS - Air France has filed a complaint to French air transport police after suspecting a smoke detector had been deliberately broken on one of its planes, the company said on Tuesday.

Air France said it complained to the air transport police (GTA) on June 9 after discovering the problem on the plane in Dusseldorf, Germany.

"A breakdown on a smoke detector was found by a pilot when the plane was on the ground," an Air France spokesman said, adding the company suspected a "malicious act".

A spokesman for the GTA said this was a "possible" theory. The complaint was first reported on www.lepoint.fr, the website of weekly French magazine Le Point.

Without citing sources, Le Point reported that a fax sent to the investigators by technicians said the wires connecting the Airbus A318 had been sliced with a cutter.

Air accident investigators are trying to establish the cause of the loss of an Air France plane over the Atlantic on June 1. The Airbus 330 crashed into the sea en route from Brazil to Paris, killing all 228 aboard.

The French air accident agency has said it is too early to pinpoint any possible cause for the crash, saying there were only two certainties - that the plane had hit stormy weather before the crash and that the speed readings were incoherent. -Reuters