A new North Korea

The regime's unabashed declarations about its nuclear weapons, which it had been much cagier about in the past, show that "it's not the same North Korea as 10 years ago," Lee said.

The United States and other global powers need to "formulate a whole new strategy" to address the changed situation, according to Lee.

"The way we've been dealing with it for the past two decades has failed," he said of the regime. "It has become close to being able to deploy nuclear weapons."

Although U.S. officials say they don't believe North Korea is in a position to strike the United States at the moment, Defense Secretary Chuck Hagel last week announced plans to deploy additional ground-based missile interceptors on the West Coast as part of efforts to enhance the nation's ability to defend itself from attack.

"The reason that we are doing what we are doing, and the reason we are advancing our program here for homeland security, is to not take any chances, is to stay ahead of the threat and to assure any contingency," Hagel said at the time.