The U.S. military's top officer overseeingoperations in Central and South America will leave his assignment well ahead of schedule, officials said Thursday - an abrupt, surprising departure as President Donald Trump shows interest in extending his administration's campaign of violence against drug cartels in the region. Navy Adm. Alvin Holsey, the head of U.S. Southern Command, will retire at the end of the year, Defense Secretary Pete Hegseth said in a statement posted on social media.