Islamic forces are attempting to takeover the area held by the secular government and are attempting to bring Ethiopia into the fight:

Somalia has not had an effective government since 1991. The country’s secular interim government, set up in 2004 and backed by the U.N., has rejected religious rule. Muslim leaders have insisted on an Islamic government.
Somalia’s internationally recognized central government holds only a small area around the central town of Baidoa, about 140 miles northwest of the capital of Mogadishu. The Islamic militiamen, meanwhile, control Mogadishu along with most of southern Somalia.
Fighting along two separate front lines continued for a fourth day on Friday, with both sides claiming victory. Around 500 Ethiopian troops with eight tanks and 30 pickup trucks mounted with anti-aircraft guns were headed for Bandiradley, an Islamic group stronghold in central Somalia, said witnesses and Islamic officials.