A Ugandan military officer serving in Somalia was killed and six other soldiers were wounded when their convoy triggered a roadside bomb, Uganda's military said on Monday, blaming fighters from the Islamist group al Shabaab.

Uganda has about 5,000 troops serving in Somalia under the African Union Transition Mission in Somalia (Atmis) peacekeeping mission.

Major Patrick Opio Awany was killed by the explosion in the village of Ceel-Werigow, around 70km southwest of the capital Mogadishu on Sunday, said Ibrahim Kasule Sekitto, a spokesman for the Ugandan troops.

Awany was commanding the convoy, which was heading from Mogadishu to Ceeljale in the Lower Shabelle region, Sekitto told Reuters.

"This attack won't deter us, it will instead stiffen our resolve to continue supporting peace efforts in Somalia," he said.

Al Shabaab has been fighting for more than a decade to topple Somalia's central government and install its rule based on its strict interpretation of Islamic sharia law.