Somalia's rebel group Al-Shabaab says that the French hostage Dennis Allex "remains safe" after French defense ministry said the captive was killed during rescue operation in the war-torn African country, the rebel group said in a statement in its twitter post.

French especial forces with helicopters raided a house in the Bulo Marer town in the south of the country in an attempt to rescue French hostage Dennis Allex who the France defense ministrty later said was killed in the operation.

Al-Shabaab militants said in its twitter post that Allex was safe and that a French solider was taken in the rescue bid during late Friday night.

"Allex still remains safe and far from the location of the battle," tweeted the militant group who claimed to have killed "several French soldiers" and that "many more were injured".

The militant group Al-Shabaab took Dennis Allex and another French national hostage in 2009 but the other hostage managed to escape from his captors.

The radical group pledged it will give its final verdict regarding the fate of Dennis Allex within two days.

The French defense ministry said following the rescue operation that Dennis Allex was killed along with two soldiers and 17 militant fighters from Al-Shabaab.