Uganda is waiting for U.S. funding to send up to 10,000 extra troops to the African Union peacekeeping force in Somalia, Uganda's Chief of Defence Forces General Aronda Nyakairima told the Daily Monitor on Tuesday.

"We can even call up to 10,000 but that will depend on whether the United States supports us or not," he said.

Only Uganda and Burundi have contributed troops for Somalia despite repeated requests by the EU- and U.S.-funded AU.

Al Shabaab, a militant Islamic militia in Somalia fighting to topple the Transitional Federal Government (TFG), claimed responsibility for an attack in Uganda's capital on July 11 that killed nearly 80 people.

The group said the attack was revenge for Uganda's deployment in Somalia and warned of further attacks if it did not withdraw its troops -- about 4,000 -- deployed in Mogadishu under the AU's more than 6,300-strong AMISOM mission.

"We don't want to overstretch our budget by calling up our (reserve) forces and then we have to even pay (their) salary," Nyakairima said.

"To my knowledge, America has undertaken to support that undertaking; that when we call up (the reserves), they will do this. But we will be waiting and see what happens," he said.