(CNN) -- African Union and Somali troops launched an offensive against militants in a densely populated enclave near the volatile Somali capital of Mogadishu, the AU mission said Tuesday.
The operation is focused on the Afgoye corridor -- populated by one of the largest concentrations of internally displaced people. Troops hope to oust the militants from the region, which is controlled by the al Qaeda-backed Al-Shabaab movement.
"Afgoye town has been controlled by the ... Al-Shabaab terrorists who have been preventing many aid agencies from operating in the area," AU representative Wafula Wamunyinyi said.
"The Afgoye corridor holds one of the biggest concentrations of internally displaced people in the world. We are helping them by building security so that they can share in the economic revival of the capital. They will now be able to access humanitarian services and eventually return to their original homes in Mogadishu."
Lt. Col. Paddy Nkunda, spokesman for the African Union Mission in Somalia, said three soldiers from the Ugandan AMISON contingent of the fighting forces have been injured. No civilians have been killed, he said. He sloughed off militant claims of deaths and more injuries. Other AMISON forces are Burundian.
Nkunda said the displaced people are being "held hostage" because they can't get aid.
"Our objective is to take Afgoye, we have advanced five kilometers today and the campaign is going well," Nkunda said. "Al-Shabaab tried to fight, but they know they are about to lose Afgoye and our soldiers broke through their early resistance."
Al-Shabaab announced in February that it was tightening its ties to al Qaeda and has long been considered a terrorist movement by the United States.
It has waged an insurgency against the feeble Transitional Federal Government since 2007 but has suffered recent setbacks in its heartland in southern Somalia.
AMISOM and government forces drove Al-Shabaab fighters from the center of Mogadishu last year, while Kenyan troops crossed into southern Somalia in October to hit back for a rash of kidnappings it blamed on the group.
But despite their efforts, Al-Shabaab has continued to launch terror attacks in the capital.