Before he left office, Barack Obama told President Donald Trump that North Korea’s growing missile program and march toward developing a nuclear weapon was the most urgent problem he would face, the New York Times reports. The report also said Obama three years ago ordered Pentagon officials to increase cyberattacks against the missile program in an attempt to disrupt test launches early on, a directive that seemingly turned out well for the U.S. as a large number of North Korea’s military rockets later exploded or veered off course.