A Coast Guard officer who kept 15 guns and other weapons in his Maryland home and allegedly planned to kill people in an attack in support of white nationalism was sentenced Friday to 13 years in federal prison in a case that illustrated the difficulty of prosecuting accused, would-be domestic terrorists who are arrested before they carry out violent crimes.

Three men who allegedly plotted "chilling" terror attacks in Melbourne were charged early Tuesday, less than two weeks after a stabbing rampage inspired by the Islamic State group left two dead in Australia's second city, police said.