An official in Somalia says a roadside bomb has killed an African Union soldier.

Floribert Biyereke, a spokesman for Burundian troops, said one soldier died after the roadside bomb exploded on Monday. Biyereke blamed the attack on the country's Islamic extremist rebels, al-Shabab.

Somalia's capital, Mogadishu, has been enjoying a relatively peaceful period following the ouster of al-Shabab from the city in August 2011.

The militant group is still blamed for infrequent suicide and roadside bomb attacks.