MOGADISHU: Armed men are attacking a hotel in central Mogadishu following a car bombing at the entrance, according to witesses and Somali police who say the Shabaab extremist group claims responsibility. "There"s an attack under way in a hotel," police officer Mohamed Adan told AFP, adding a "car bomb" exploded at the entrance and "armed men have raided the building." Adan added: "There is an exchange of fire." Police said there were casualties but numbers were unknown. The militant group al Shabaab frequently carries out bombings in its war on Somalia"s government, which is backed by the United Nations and African Union (AU) peacekeeping troops. According to Reuters, security forces besieged the area, where cars are inspected en route to the airport and where politicians regularly gather at the hotel. Police spokesman Sadik Ali said many people had been rescued from the Hotel Afrik. "There must be casualties because the militants first started the attack with a suicide car bomb against the wall," he told Reuters. "The operation still goes on, casualties will be known later." Al Shabaab is allied with al Qaeda and wants to rule Somalia according to its interpretation of Islamic sharia law.