TENS of thousands of migrants, mostly Ethiopians, are stranded in Yemen and at least 14,500 have been rounded up and forcibly transferred internally amid fears migrants contribute to the spread of COVID-19, the U.N. migration agency said on Tuesday. Thousands of Saudi-bound Ethiopian workers cross Yemen each month but restrictions aimed at curbing the rapid spread of COVID-19 in the war-ravaged country have cut arrivals. But among those already there, thousands have been bussed or trucked to cities like Aden and Marib where they are now stuck, the International Organization for Migration (IOM) said. "It's a very dire situation when…