A large explosion was heard Sunday near the Somali town of Afgoye, an al Shabaab insurgent stronghold 30 km from the capital Mogadishu, residents and a senior rebel official said.

Afgoye is on a list of 10 Somali towns the Kenyan military said risked air strikes in its campaign against the insurgents. It is a strategic junction on the road leading from the capital to the south of the Horn of Africa nation.

Kenya's military spokesman was not immediately available for comment.

(Reporting by Mohamed Ahmed and Abdi Sheikh; Editing by David Clarke)