Al Qaida's North African branch said its attack on a beach resort in Ivory Coast on Sunday that killed 18 people was revenge for a France's offensive against Islamist militants in the Sahel region and called for its forces to withdraw.French Foreign Minister Jean-Marc Ayrault and Interior Minister Bernard Cazeneuve arrived on Tuesday to reassure the large French community and boost the investigation into the attack in Grand Bassam, in which four French citizens died.Three Ivorian special forces personnel were killed and three of the attackers were also among the dead.The statement by Al Qaida in the Islamic Maghreb was posted on the group's social media accounts on Monday.