The Somali army and forces loyal to the semi-autonomous southern Jubaland region have clashed, Somali government and military officials said Wednesday.
Conflict-weary Somalia is a federation of five semi-autonomous member states -- Puntland, Jubaland, Galmudug, Hirshabelle and South West -- and a central government in the capital Mogadishu.
Tensions have been rising between the central authority and Jubaland, most recently with the region's re-election of a former warlord Ahmed Madobe, labelled "unlawful" by Mogadishu.
Both sides claimed victory in the clash, which broke out early Wednesday near the southern peninsula of Ras Kamboni, some 290 kilometres (180 miles) from Kismayo city.
"Members from the Jubaland forces, who are being misused by Ahmed Madobe, attacked the military base of the Somali national army and Jubaland forces in the Lower Juba region," the Ministry of Defence said in a statement.
The ministry also claimed that Madobe had made a deal with Al-Shabaab allowing his forces to pass through territory held by them.
"These treasonous acts will not go unpunished," the ministry warned in its statement.
The Jubaland administration said they had been attacked, claiming the Somali army "launched an assault on the military base of the Jubaland forces".
"They have started their assault with drone strike and the fighting has intensified," local deputy security minister Adan Ahmed told reporters in Kismayo.
He also claimed a number of soldiers had surrendered. AFP was unable to verify that information.
Communications remain difficult in the region and information is scarce.
City resident Mohamed Adan told AFP that he had seen armed "military mobilisation", without giving further details, before adding that "people also sighted military helicopters outside Kismayo this morning".
The election of Madobe irked Mogadishu as authorities -- who have struggled with decades of instability -- had hoped to align Jubaland's polls with plans to introduce nationwide universal suffrage elections next year.
The tensions in Jubaland will also worry neighbouring Kenya and Ethiopia, who see Jubaland as a buffer against Al-Shabaab militants who have staged several bloody attacks in their countries.