Hundreds of African migrants were stranded in dire conditions in a desert area of southern Tunisia on Thursday after being expelled from the port city of Sfax, witnesses told AFP.Racial tensions flared this week into violence targeting migrants from sub-Saharan African countries, with dozens fleeing the city or being forcibly evicted."I came because I'd heard that human rights were respected in Tunisia, but what is happening shows that this is not the case," said 27-year-old Issa Kone, from Mali.