MOGADISHU (Reuters) -Somali government forces were fighting on Saturday to repel al Shabaab militants who stormed a high-security underground prison in the capital Mogadishu, a witness and the government said. Godka Jilaow, near the Villa Somalia presidential palace compound, houses several fighters from the al Shabaab group, which has waged an insurgency in Somalia since 2007 and made significant advances in the countryside this year. Al Shabaab claimed responsibility for the attack. “We targeted the underground cell guarded by security forces. In a statement on state television’s Facebook account, the government said al Shabaab fighters used a car disguised as a vehicle from the security forces to blast their way in.