54 Ugandan peacekeepers were killed during last week's siege by militants on an African Union base in Somalia, Ugandan President Yoweri Museveni wrote on Twitter.

“We discovered the lifeless bodies of 54 fallen soldiers, including a commander,” he said.

Al-Shabaab, a terrorist group that has been fighting against the Somali central government for over a decade, claimed responsibility for the May 26 attack, saying it seized the base.

A local resident and a Somali military commander told AFP the militants drove a car loaded with explosives into the Bulo Marer base, 120 kilometers southwest of the capital Mogadishu.

The death toll is one of the highest since pro-government forces, supported by AU forces known as ATMIS, launched an offensive against al-Shabaab in August of last year.

The ATMIS forces include representatives from Uganda, Burundi, Djibouti, Ethiopia and Kenya, and troops are stationed in southern and central Somalia.