At least 100 people have been killed and 300 wounded in two car bomb explosions in the capital Mogadishu, Somali President Hassan Sheikh Mohamud said.

Blaming the al-Shabab armed group for the attacks, Mohamud told reporters on Sunday that he expected the death toll from the twin blasts to rise further.

Authorities said the attack at the busy Sobe intersection on Saturday targeted the Somali education ministry and a school.