. >> the authorities in kenya, uganda, tanzania, burundi had issued alerts over possible terror attacks over the christmas holiday. we have this report. >> the struggle for power in somalia has long been a local dispute with neighbors of war- torn countries increasingly concerned that the islamist threat has crossed borders. until this week, the main somali islamist groups fought for territory. but now, the main opposition force has allies. >> after successive meetings of relentless debate between the leadership of al-shabab, the day we have been waiting for has arrived. >> the two militant groups controlled much of somalia. this is protected by an 8000- strong african union forced, and it is the countries that sent troops that al-shabab say they will first attack. this week, the u.n. says troops will be boosted by 50%. but it's the weakest neighbors' concerns ride on the kenya, where a blast was gained on the -- was blamed on al-shabab. what's in calling on the public to avoid public places. -- >> i am calling and the public to avoid public places. >> somalia is seen by the west as a b