By Tim Cocks BBC News, Antananarivo

The soldiers were travelling on a French military plane from the Malagasy capital, Antananarivo, to Reunion.

The carcasses were from two species found only in Madagascar's south - the radiated and spider tortoises.

Environmental groups said the incident highlights a major risk to the island's unique wildlife.

Police in Reunion made the discovery during a routine check of a French military plane carrying 40 or so Malagasy soldiers.

Lucrative trade

Three men were arrested and an official investigation launched. French officials want to know where the smuggled goods came from and where they were intended to go next.

Sources at the French embassy in Madagascar said this was the first time anyone had been caught using French military planes to smuggle endangered species.

Environmental groups said the case highlights a persistent problem on the huge Indian Ocean island, which is regarded as a biodiversity hotspot by conservationists because of its 200,000 or so species of plant and animal life, three-quarters of which are found nowhere else in the world.

Environmentalists say both are a target for poachers who sell them to a lucrative export market mostly focused on Asian countries such as Thailand or Japan.

Tortoise livers are chopped out and used in traditional medicines, tortoise shells are torn off and used to make jewellery while their skin often starts a new life as a part of a handbag or a pair of shoes.