A Somali police official says a car bomb has exploded near a police station in a busy market in the Somali capital, killing at least four people and injuring nine others.

Capt. Mohamed Hussein said the bomber targeted a police station in Mogadishu's Waberi neighborhood, where President Hassan Sheikh Mohamud had been visiting a university Saturday.

There was no immediate claim of responsibility for the attack, but the al-Qaida-linked Islamic extremist group al-Shabab often carries out such attacks.

Despite being ousted from most of its key strongholds in south and central Somalia, the group continues to launch deadly guerrilla attacks against the Somali government and African Union forces across large parts of the horn of Africa nation.