( CNN ) -- Dozens of African Union soldiers have been killed in two weeks of fierce fighting in Somali capital of Mogadishu , clashes that resulted in significant gains against local and foreign extremists , according to an African Union official familiar with the scale of those losses . The fighting was part of a major offensive by Ugandan and Burundian forces , who are part of the African Union Mission in Somalia ( AMISOM ) , against Al-Shabaab , an al Qaeda-linked extremist group trying to take over the weak transitional federal government and implement a stricter form of Islamic law , or sharia . AMISOM officials said they would not specify exactly how many soldiers have been killed or wounded in the operations until the families and contributing countries were properly notified . Also , they did n't detail Al-Shabaab losses . `` This loss of life comes in an intently meaningful and honorable victory , one which will ensure that many more lives will be saved in the long run , '' Wafula Wamunyinyi , a senior AMISOM official , told reporters in Nairobi , Kenya . `` The positions that we have seized in the past week break the grip of extremist militants in the city . We have taken a very important step towards the stabilization of Mogadishu and in pursuit of a day many deemed impossible -- the day when law and order returns to Mogadishu , '' Wamunyini said . The operations began on February 19 with the clearance of a network of urban trenches by Ugandan forces . That battle uncovered further proof that foreign fighters are playing a key role in the leadership of Al-Shabaab , originally a homegrown Somali movement . According to AMISOM , several key foreign fighters were killed in the operation . `` Al-Shabaab is organized like an Al Qaeda operation , '' said force commander Maj. Gen. Nathan Mugisha , `` their tactics are replicated from Afghanistan . '' On February 23 , Burundian forces successfully took two key Al-Shabaab positions in fierce fighting -- the former Ministry of Defense buildings ( known as Gashindiga ) and the former milk factory , according to Mugisha . Located in northeastern Africa , Somalia has not had a stable government since 1991 , and fighting between the rebels and government troops has escalated the humanitarian crisis in the famine-ravaged country . One U.N. humanitarian official said on Friday voiced urgent concern about the `` increased displacement '' caused by the fighting and the effects of drought there , said Valerie Amos , under-secretary-general for humanitarian affairs . She visited Somalia last month and talked to reporters on Friday . `` I again urge all parties to the conflict and AMISOM ( the African Union peacekeeping mission in Somalia ) to comply with international humanitarian law in order to minimize harm to the civilians , '' Amos said .
The fighting was part of a major offensive . The operation began February 19 . Ugandans and Burundians are part of the AU mission .