Somalia's Shebab Islamists said Thursday they have executed a French agent they had held since 2009, as France said the hostage was likely killed several days ago in a failed rescue attempt. "16:30 GMT, Wednesday, 16 January, 2013. Denis Allex is executed," the group said on its Twitter feed Thursday, with the report confirmed by a senior Shebab official who said the group might release audio and video of the "execution." "Audio and video are available and will be released any time we decide," he told AFP, saying the hostage, whose name is likely a pseudonym, was killed in Bulomarer, a town south of Mogadishu still under Shebab control. French commandos on Saturday launched a raid on the town to free the hostage, but the bid failed and resulted in the death of two French soldiers. The al-Qaeda linked Shebab said Wednesday they had "reached a unanimous decision to execute" their hostage in order to avenge "the dozens of Muslim civilians senselessly killed by the French forces during the operation." Witnesses said eight civilians died during the raid to free Allex. The group also cited "France's increasing persecution of Muslims around the world, its oppressive anti-Islam policies at home, French military operations in Afghanistan and, most recently, in Mali." The French army on Wednesday accused the Shebab of "manipulating the media" and reaffirmed that Allex was likely already dead. "We suspect, and I believe that we are not wrong to do so, that Somalia's Shebab are manipulating the media," France's Chief of Defence Staff Admiral Edouard Guillaud said on Europe 1 radio. "We have no element since the raid indicating Denis Allex is alive. We think he is most likely dead," he said. In the operation to free Allex, two other French soldiers were killed. The French retrieved one of the bodies. Pictures of the second soldier, presented by the Shebab as the commander of the raid, have been posted on the Islamists' Twitter account. French Defence Minister Jean-Yves Le Drian said Saturday that the raid, by the elite DGSE secret service, was sparked by the "intransigence of the terrorists who have refused to negotiate for three and a half years and were holding Denis Allex in inhuman conditions." The minister said at the weekend that a French soldier was missing, but on Monday he said it now appeared that the soldier had died. He did not indicate that he was a commander. Le Drian said 17 guerrillas were killed in the raid. Sources in Somalia said one of the reasons the raid failed was that the rebels had received advance warning, which senior Shebab commander Sheikh Mohamed Ibrahim confirmed to AFP by telephone without giving further details. Le Drian's explanation was that French troops had underestimated the Islamist rebels' strength when they launched the operation involving some 50 troops and at least five helicopters - and some help from Washington. President Barack Obama has acknowledged that US forces provided limited technical support for the operation, but said they had played no role in the fighting. Denis Allex is the longest held French hostage overseas since French-Colombian Ingrid Betancourt, who had been held for more than six years by Colombian guerrillas until being rescued by Colombia's security forces in 2008. Source: AFP