The African Union has begun its withdrawal from Somalia to cut 1,000 troops by the end of this year as security responsibilities start to shift to the local military. The continental body said on Tuesday that the move comes at a critical time, less than a month after the country’s worst attack killed more than 350 people, AP said. The Somalia-based Al-Shabab extremist group has been blamed for the attack. The AU hopes its troop movements will not cause alarm. Officials said earlier that the first troops would leave in 2018. The 22,000-strong African Union force in Somalia is expected to have fully withdrawn by the end of 2020.