SUDAN - The United States is pulling its embassy staff out of South Sudan in the wake of a failed government coup. The U.S. embassy is evacuating as an alleged attempt to overthrow president Salva Kiir Sunday escalates into a bloody civil conflict. More than 500 people, most of them soldiers, have been killed so far. The violence pitting soldiers loyal to Kiir against those loyal to former vice president Riek Machar. United Nations Secretary General Ban Ki Moon is appealing to Kiir to stop the violence and respect human rights.