"Suspected AlShabaab militants fired mortar shells at densely populated civilian residential areas in Baidoa town this morning," the African Union peacekeepers said on Twitter.
One round of the mortars hit a hospital, the mission said. The AMISPM has no information about civilian casualties but says they are expected.
"This incident further attests to AlShabaab terrorists’ cruelty and total disregard for the lives of the Somali people," the mission said.
Somalia has been experiencing violence since the country devolved into civil war in the early 1990s. The state’s collapse provided a breeding ground for warlords, pirates and the al-Qaeda affiliated al-Shabaab. The AMISOM was deployed in the country in 2007.