“Joint military exercises conducted by the South Korean authorities with external forces century after century are the root cause of the escalation of tension on the Korean peninsula and blocking the development of inter-Korean relations,” the letter of the Committee quoted by Interfax says.

The DPRK warned that they would be forced to take "countermeasures to eliminate potential and direct threats to their security."

Earlier, the DPRK Foreign Ministry called the begun command and staff exercises of South Korea and the United States "a violation of a number of agreements."