Reports indicate that three Somali soldiers gunned down 15 Kenyan troops near the southern town of Taabto, escaping with Kenyan military trucks.
Meanwhile, Somali military officials are arguing that the soldiers killed the Kenyan troops by mistake.
The deaths took place only hours after the recent killing of at least 64 people in southern Somalia by US drone attacks and Kenya airstrikes.
Earlier, US assassination drones claimed the lives of some 24 Somalis.
Last month, Kenya dispatched soldiers over its border into Somalia and began air and ground offensives against al-Shabab fighters.
Tension has been growing between the Somali government backed by Kenyan troops and al-Shabab fighters since they engaged in fierce battle over control of towns in south Somalia.
Somalia has not had a functioning government since 1991, when warlords overthrew former dictator Mohamed Siad Barre.
Strategically located in the Horn of Africa, Somalia remains one of the countries generating the highest number of refugees and internally displaced persons in the world.
