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 Tuesday in the heavy-artillery pre-dawn fire.
Military officials say 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 also has sent its troops into Somalia to fight the rebels. Nairobi blames al-Shabab for abductions of foreign tourists from its territory.
Some information for this report was provided by AP and AFP.