A U.S. soldier stationed in South Korea crossed the heavily armed border into North Korea without authorization and is believed to be in North Korean custody, officials said Tuesday.White House spokeswoman Karine Jean-Pierre and other officials said the soldier went "willfully" across the military demarcation line into North Korea in the afternoon local time.Defense Secretary Lloyd Austin also told a press conference, "We believe that he is in (North Korea's) custody. And so we're closely monitoring and investigating the situation and working to notify the soldier's next of kin and engaging…READ FULL ARTICLE