Ethiopian soldiers have begun their withdrawal from Somalia
Clashes between rival Islamist militia groups in Somalia have killed about 30 people and injured more than 30 others.
The fighting in Guriel, 500km (310 miles) north of the capital Mogadishu, involved the hardline group al-Shabaab and a local militia, witnesses said.
Correspondents say that a power vacuum may be opening up as the 3,000-strong Ethiopian force pulls out of Somalia.
Ethiopian troops arrived in Somalia in 2006 to help the interim government oust Islamists from the capital.
The Ethiopian intervention was deeply unpopular with many Somalis.
But while some now fear their withdrawal could lead to a power vacuum, others say it could make it easier for a new government to be formed, including moderate Islamist forces.
Various Islamist and nationalist groups now control much of southern Somalia. Government forces only control parts of Mogadishu and the town of Baidoa.
Somalia has not had an effective national government since 1991.
Al-Shabaab, which opposes a peace deal with Somalia's transitional government, is trying to take control of areas vacated by the Ethiopians - Guriel was one such town.
"It was the heaviest clash ever in the region between the two sides," a local elder, Abdulahi Hirsi Moge, was quoted by AFP as saying.
"We have counted at least 25 people, most of them combatants, killed in the fighting and there is still a possibility of some undisclosed dead bodies outside of the town," he added.
About 3,400 Ugandan and Burundian peacekeepers from the African Union in Somalia are taking up positions vacated by the Ethiopians in an effort to stem the violence.