It is not clear if any Somalis were hit by the shells, fired as Islamist insurgents continue to battle government forces. Those killed were from Uganda, one of just two countries to have sent troops to Somalia to help the government. Last month, at least 76 people were killed in Uganda in bombings which a Somali group said it had carried out.
The battle for control of Mogadishu has intensified in the past week. Last Monday, a suicide attack on a hotel killed at least 32 people, including six MPs. The Islamist group al-Shabab said it had carried out the attack. Last month, al-Shabab said it was behind two bombings in the Ugandan capital, Kampala, in which more than 70 people died.
Al-Shabab, which has links to al-Qaeda, controls much of southern and central Somalia, while the government – backed by the 6,000-strong African Union peace force – is confined to a few pockets of the capital.
But on Monday, President Sheikh Sharif Sheikh Ahmad appealed for more international help to contain the “evil al-Qaeda-al-Shabab alliance”. Last month African leaders agreed to send an extra 2,000 troops to Mogadishu. Meanwhile, there are reports that Ethiopian troops have been crossing into Somali over the last two days.
An unknown number of Ethiopians, with armoured cars, have carried out operations against al-Shabab insurgents in an area 20km (about 12 miles) inside Somalia towards the central town of Beledweyne. Al-Shabab has been fighting a pro-government militia for control of Beledweyne in recent months.