Somali police say at least 4 civilians died in a roadside bombing in the Somali capital, Mogadishu.

Police suspect the bombing Tuesday was intended for African Union Peacekeepers who are protecting the fragile Somali government from Islamist militants.

The insurgent group al-Shabab is trying to topple the United Nations-backed government and turn Somalia into a strict Islamic state.

Al-Shabab rules much of southern and central Somalia, while the government controls only small parts of the capital.

However, government and African Union forces have retaken parts of Mogadishu in an offensive that began in February.

Somalia has not had a functioning central government since the fall of dictator Mohamed Siad Barre in 1991.