At least 15 officers were killed in Somalias capital Mogadishu on Thursday when a suicide bomber from the Shabaab militant group disguised as a policeman blew himself up inside the General Kahiye Police Training Academy, officials said. Police spokesman Major Mohamed Hussein said the attacker had explosives strapped to his body and infiltrated the training camp during an early morning parade. "So far 15 have died and 17 others were injured," Abdullahi Nur, another police official, told Reuters. Earlier, the head of a local ambulance service said they had moved the bodies of 13 victims as well as 15 injured people. Officers said the toll could have been far worse had the attacker killed himself in the center of the crowd. Shabaab claimed responsibility for the attack and gave a higher death toll. "We killed 27 police (officers) and injured more," Abdiasis Abu Musab, the groups military operations spokesman, told Reuters. Shabaab carries out frequent bombings in Mogadishu and other towns. The group, which is allied to al Qaeda, is waging an insurgency against the UN-backed government and its African Union allies. The militants were driven out of Mogadishu in 2011 and have since been steadily losing territory to the combined forces of African Union peacekeepers and Somali security forces.