Somali National Army (SNA) and African Union Mission (AMISOM) forces arrested several Shabab fighters in a joint operation in southern Somalia on Sunday, the AU mission said on Monday.

AMISOM said its Burundian contingent based at Gololey joined the operation, flushing out militants hiding in the Sayga forest.

"A number of al-Shabab fighters were captured and handed over to the Somali police for further investigations," AMISOM said in a statement.

The operation was aimed at ensuring free movement of Somali people on the main supply route of Mogadishu-Jowhar, the statement said.

Al-Shabab, which has been seeking to topple the government, has continued to restrict the movement of people and control supply routes to most of the recovered areas, according to Somali authorities and humanitarian partners.

AU troops have been conducting regular patrols and escorting vehicles carrying humanitarian relief aid and participated in combat operations against al-Shabab to secure main supply routes.

There have been clashes in southern and central Somalia between government forces and al-Shabab since the militants were chased out of the capital Mogadishu in August 2011 by allied forces.