For nearly six decades, South Korea's (ROK) approach to security has focused on sustaining the status quo: Maintaining deterrence and a robust defence posture in order to prevent another major conflict on the Korean Peninsula.

Asked whether it was effective to deal with the issue by publicly naming China, Hagel said he thought both public diplomacy and private engagement were necessary. Public statements are necessary to let people know what is going on, he said, but it doesn't solve problems.

For the last few decades, Iran has been making headlines in global media for its defiant standing against western powers on a number of issues. It is suspected by western powers that Iran is running its clandestine nuclear program for military purpose but the US officials are yet to find any solution.