U.S. special operations troops in South Korea praised recent training where they prepared for unexpected threats at a time when global crises are more interconnected than ever, their commander said following the exercise last week.

"Nothing in the history of the United States should give us any faith and confidence that we know where the next threat is coming from," Brig. Gen. Derek Lipson of Special Operations Command — Korea said in an interview on the sidelines of joint drills.

Nuclear-armed North Korea in recent years has made unprecedented strides in its weapons programs, including massive new ballistic missiles that can reach the United States and speedy new tactical missiles designed to defeat missile defense systems.