On this edition of Africa 54: U.N. Secretary-General Antonio Guterres hit back at Ethiopia over the government's expulsion of seven U.N. staff, demanding proof of accusations against them; the humanitarian agencies operating in Somalia and Somali officials say they deeply regret the arrests and forced displacement of thousands of people who have been expelled from the town of Las Anod by authorities in the self-declared republic of Somaliland; & in Burkina Faso, at least 400 people have been awaiting trial on terrorism charges for years, including several minors under the age of 16.