News reports from Somalia say that African Union troops have clashed with al-Qaeda-linked Somali rebels in Mogadishu.

It is not clear how many casualties were involved in the heavy-artillery pre-dawn fighting Tuesday.

Military officials say that the AU peacekeepers from Burundi backed by the transitional Somali government troops launched an offensive on al-Shabab bases on the outskirts of Mogadishu to secure the Somali capital. They said the operation was successful.

But al-Shabab news media quoted rebel sources as saying that their forces were victorious against peacekeepers and killed at least seven.

Al-Shabab wants to impose a strict version of Islamic law in Somalia. The group controls a large part of the country and is fighting to take over the capital, Mogadishu, which is held by a weak internationally-supported government.

Kenya has also sent its troops into Somalia to fight the rebels. Nairobi blames al-Shabab for abductions of foreign tourists from its territory.