Kenya's armed forces said they had thwarted an assault by Shebab jihadists on a military camp in southern Somalia early Wednesday, killing 19 insurgents and seizing a haul of weapons.

Kenyan troops operating under the African Union Mission to Somalia (AMISOM) "foiled a planned attack" by Shebab militants near a camp operated by the Somali National Army and AMISOM at Afmadhow in the Lower Juba area, the Kenya Defence Forces (KDF) said in a statement.

"The... terrorists had approached the camp at night with the intent to attack and cut off the SNA from the AMISOM KDF camp," it said.

"KDF soldiers on patrol identified the militants and engaged them in a fierce battle. The (Shebab) attempted to fight back, but were swiftly repulsed by the KDF soldiers on patrol and those at the camp," it said, quoting army spokesman David Obonyo.

"Following the incident, 19 (Shebab) militants were killed and one technical vehicle destroyed. Some of the arms and ammunition recovered include 10 AK 47 rifles and three rocket-propelled grenades."

The KDF statement could not be immediately confirmed independently.

The al-Qaeda-aligned group was ousted from the capital Mogadishu in August 2011 and today concentrates on carrying out attacks from the countryside.

It has claimed responsiblity for a string of recent attacks in Somalia, including a twin bombing in the city of Baidoa on February 28 that killed at least 30 people.

On January 15, Shebab fighters overran a military outpost in El-Adde, southern Somalia, manned by up to 200 Kenyan soldiers deployed under AMISOM.

Shebab fighters are targeting AMISOM because in the absence of a functioning national army, the 22,000-strong force is the only protector of the internationally-backed government that the jihadists are committed to overthrowing.