Fighting erupted between Islamist rebels, government forces and African Union (AU) peacekeepers in Somalia's capital Mogadishu on Friday, killing at least 22 people, witnesses and medical staff said, Reuters reported. Battles broke out around the city's strategic K4 junction after the insurgents launched a pre-dawn attack on an AU base and on government troops. Witnesses said the clashes spread to three other districts and that most of the dead were civilians. The toll was expected to increase as the fighting continued through the morning. Fearful residents cowered in their homes as mortar shells detonated around them and bullets tore into walls. "We have seen 17 dead people and taken 40 others to hospitals," senior ambulance official Ali Musa told Reuters. The international community wants to bolster the U.N.-backed government of President Sheikh Sharif Ahmed, which is fighting several rebel movements including al Shabaab. The United States says that group is al Qaeda's proxy in Somalia. Battles have been taking place across central and southern regions this week as pro-government militia try to seize towns from al Shabaab and another insurgent group, Hizbul Islam. At least 33 people died at Bula Burde in the southern Hiran region on Thursday, and 12 more died when al Shabaab fighters drove pro-government gunmen out of Bulahawa. -- SPA