A large explosion outside a school in Somalia's capital Mogadishu on Thursday killed at least eight people, including students, witnesses said.

The extremist group al-Shabaab claimed responsibility for the attack.

The al-Qaeda-linked group controls large parts of rural Somalia and continues to frustrate efforts at rebuilding the Horn of Africa nation after three decades of conflict, CBC reported.

The blast sent a plume of smoke above a busy part of Mogadishu during the morning rush hour.

Police spokesman Abdifatah Adam Hassan said eight people were killed and 17 others wounded.

Al-Shabaab in a statement carried by its Andalus radio said it targeted Western officials being escorted by the African Union (AU) peacekeeping convoy.