A French M51 ballistic missile self-destructed off the coast of Brittany during a test on Sunday, according to media reports. The missile \"self-destructed during its first propulsion phase... for an unknown reason,\" Lieutenant Commander Lionel Delort, a spokesman for the Atlantic Naval Prefecture, was quoted by AFP as saying. \"It was a failure, the reasons will be determined by an investigation,\" said the spokesman. The test-fire was carried out from the Vigilant strategic nuclear submarine in the Bay of Audierne at 0730 GMT. The missile was not carrying a nuclear warhead and landed in the ocean after its destruction. The M51 was put into operation in 2010 after five successful test launches and has a range of 8,000-10,000 km.