French officials say a military agent held hostage in Somalia since 2009 has been killed during an overnight raid by French troops trying to rescue him.

The French Defense Ministry said Saturday Denis Allex was killed by his captors along with two French soldiers who died in the rescue attempt. The Ministry says 17 Somalian fighters were also killed.

However, the French news agency quotes al-Shebab insurgents as saying Allex remains safe far from the battle area after what the militants described as a botched rescue operation.

Earlier reports from southern Somalia said French commandos attempted to rescue the French security advisor who was kidnapped in Mogadishu more than three years ago.

Residents in the town of Boulmarer say they heard gunfire and explosions shortly after spotting helicopters in the air. They also report seeing a number of casualties after the clash, although the identities of the dead were not clear.