Mogadishu , Somalia ( CNN ) -- Somalia 's top militant group may soon counter the government 's recent thrust against them with an offensive of their own . African Union intelligence sources say Al-Shabaab is massing hundreds of troops in the African nation 's embattled capital of Mogadishu for a show of force during the Muslim month of Ramadan , which begins Monday . The sources said Al-Shabaab received a shipment of weapons by sea in preparation for this offensive . They believe that Al-Shabaab allies in Yemen shipped the items across the Red Sea to Somalia . Ramadan is a period of fasting and religious reflection . Islamic radicals have chosen the period to carry out attacks against their enemies during the holy month . Fighting has intensified this summer as Somali government forces -- backed by troops from the African Union -- have battled insurgents from the militant Al-Shabaab . Somali government forces on Thursday launched an offensive on Islamist strongholds in northern Mogadishu . The U.N. refugee agency on Friday expressed concerns about `` the protection of civilians '' in Mogadishu amid the fighting . But African Union forces said the offensive was launched to counter Al-Shabaab attacks on displaced persons camps . `` An offensive on Thursday by pro-government forces in and around the important Bakara and Balcad markets has increased the risk for Mogadishu 's citizens as well as the estimated 100,000 internally displaced people ( IDP ) who have fled drought and famine in neighbouring regions in recent months , '' the U.N. High Commissioner for Refugees said . Since September , African Union forces said they have steadily been taking territory in the capital from Al-Shabaab . The fighting comes also as Somalia is battling its worst drought in 60 years and tens of thousands of famine-stricken people are walking for days into both Kenya and Ethiopia in search of food and water and away from the conflict between government forces and rebels . The United Nations on Friday said it is asking for a further $ 1.4 billion to help starving people across the Horn of Africa . The request lifts the Horn of Africa appeal to $ 2.4 billion , of which $ 1 billion has been received so far . `` More than 12 million people -- in Kenya , Ethiopia , Somalia and Djibouti -- are in dire need of help , and the situation is getting worse , '' said Valerie Amos , U.N . Emergency Relief Coordinator and head of the Office for the Coordination of Humanitarian Affairs . `` If we are to avoid this crisis becoming an even bigger catastrophe , we must act now . '' Meanwhile , Erastus Mwencha , the African Union Commission deputy chief , visited Mogadishu to assess the humanitarian situation and announced an international pledging conference August 9 in Ethiopia . The African Union has already donated $ 500,000 of assistance in the famine .
NEW : The African Union announces a pledging conference for famine relief . AU sources says Al-Shabaab got a shipment of weapons by sea . TL;DR A Kenyan official tells CNN that the militants have been driven out from their last stronghold in Somalia. The U.N. has issued another appeal for aid money .