There are things called satellites, the usa can monitor ukraine and other eastern european with ease. They can certainly do that since they have bases in Kenya and Djibouti. No way all these forces moving to one single location wasn't noticed by anyone.You think thousands of kilometres is constantly monitored by UAVs? Just Gedo is larger than many countries
The only time strikes happen is when there’s intelligence and no citizens. Shabaab use human shields which means no strikes anytime they bring along anyone