More troops pledged
Nigeria, Burundi, Ghana and Malawi have also pledged troops to the AU misson, but it is unclear when they would mobilise them.
"The other forces would have to take control of other main towns - Kismayu, Baidoa, Jowhar, Marka," Ankunda said.
"The African Union must compel [the others] to send forces."
Ankunda said the Ugandan troops were able maintain control by themselves until reinforcements arrive, because they had the necessary training and equipment.
International pressure has grown for peacekeepers to deploy quickly to Somalia to prevent the east African country from sliding back into anarchy.
Ethiopian forces helped the transitional government defeat forces allied to the Islamic Courts in a December war but the government remains weak and unable to fully control the country.
The Islamic Courts had restored a degree of order to Mogadishu, which had been ruled by rebel forces since the overthrow of Mohamed Siad Barre's regime in 1991.
However, the United States and Ethiopia had accused them of harbouring al-Qaeda operatives and helped the internationally-recognised government regain control over the impoverished country.