The armed Islamist group al-Shabab has said it has decided to execute a French intelligence agent who has been held captive for three years and was the object of an unsuccessful rescue bid in Somalia on Saturday. The al-Qaeda-linked group released a statement on Tuesday saying it had “reached a unanimous decision to execute the French intelligence officer, Denis Allex”. “With the rescue attempt, France has voluntarily signed Allex’s death warrant,” said al-Shabab. A senior al-Shabab official told the AFP news agency that Allex “has been sentenced and this judgement will not be changed”. “As far as we are concerned this man should die,” he added. French officials had previously said that Allex, presumed to be an alias for the agent, was most likely killed by his captors during the failed rescue attempt, which left two French soldiers and 17 rebels dead. French troops retrieved the bodies of one of the soldiers killed in the attack, and Jean-Yves Le Drian, the French defence minister, said on Saturday that the other soldier was missing, presumed dead.