Witnesses say fighting in Somalia's capital has killed at least 8 people and wounded 15 after Islamic insurgents attacked an African Union peacekeeping base.

A spokesman for the AU force, Bahoku Barigye, said no peacekeepers died in Tuesday's attack or the subsequent fighting.

Witnesses report seeing at least 8 corpses.

The powerful al-Shabab insurgent group is trying to topple Somalia's government and install strict Islamic law. Last week, they launched two suicide car bombs on the main African Union base, killing 21 people. It was the deadliest single attack on peacekeepers since they arrived in 2007.

There are increasing concerns that al-Shabab's ties to al-Qaida are growing.