What’s behind the latest attack in Somalia?

People in Mogadishu are in mourning once again. At least 120 people were killed when two car bombs exploded outside the Ministry of Education on Saturday. The government says the militant group al-Shabab were behind the attack - their deadliest for five years. President Hassan Sheik Mohamud says he will wage a full war on those responsible. So, what is behind the latest attack? And what can be done to stop the militants?#AfricaDaily