After it suffered a two-day outage of all of its websites based in the country, North Korea is accusing the United States and South Korea of conducting a cyber attack against it.
North Korea's state news agency says the country's “internet service bases” were hit by “concentrated and persistent virus attacks” for several days this week.
The Korean Central News Agency blames the United States and South Korea, saying they “will have to take the responsibility for the whole consequences.”
Some Internet users in various countries noted that for most of Wednesday and Thursday all web sites with the dot kp domain suffix were unreachable.
The entire North Korean domain is always blocked by South Korean Internet service providers and reposting such content in the South is a crime.
A spokesman for South Korea's National Intelligence Service, who declined to give his name, tells VOA the spy agency is still trying to trace the source of the unprecedented sustained problem affecting the North's web sites.
North Korea says it cannot be overlooked that it was hit by a cyber attack while the Key Resolve joint military exercises are underway in the South.
South Korea's military Joint Chiefs of Staff says the purported cyber attack on North Korea is not in any way connected to the Key Resolve drill.
The nerve center for the drill is the Korea Battle Simulation Center at the U.S. Army's Yongsan Garrison in the South Korean capital.
It is being led by South Korea's Joint Chiefs of Staff.
A group of reporters was briefly permitted Friday inside the battle simulation center where U.S. Army Lt. Colonel Elton Roberts explained the facility's purpose.
“It is a computer-assisted war game simulation planned and operated by subject-matter experts. And it's uniquely tailored for each exercise in accordance with the training goals of the commander of the exercised unit,” he said.
It was revealed Friday that a new Wargaming Facility, designed for those playing the role of the North Korean forces, has opened at Suwon Air Base, 30 kilometers south of Seoul.
For Key Resolve, the mock opposing forces are augmented by hundreds of military personnel from South Korea and the United States. They are led by a retired South Korean marine brigadier general.
U.S. Forces Korea's Jude Shea, who is the director of the Korea Battle Simulation Center, was asked if the North Koreans ever win during the exercises.
“Yes, on occasion, the opposing force will win the battle or gain the upper hand. And, of course, that's part of the training benefit because if the good guys always won the amount of training benefit in the exercise would not be nearly as great as if periodically the opposing force does better,” said Shea.
Key Resolve involves more than 3,000 personnel in a total of 11 simulation centers in South Korea, Japan and the United States, linked by computer and video.
Military officials will not release the specific scenario for the computer-simulated training phase of Key Resolve, which began Thursday, but acknowledge the current situation on the Korean peninsula is factored into it.
North Korea has strongly condemned the drill, along with a separate but overlapping joint exercise - Foal Eagle - also involving thousands of forces, calling it a prelude to a nuclear strike on the country.
Pyongyang, in recent days, has stated that the war games in the South compel it to prepare to preemptively conduct a nuclear attack of its own on the United States and South Korea.
A spokesman for South Korea's Ministry of National Defense, Kim Min-seok, declines direct comment on a Seoul newspaper's report that the North has moved (170mm) self-propelled artillery and (240mm) multiple rocket launchers to just across from Baengyeong island on the Yellow Sea frontier.
Kim says such exercises as the current Key Resolve drill help the South to be prepared for all-out provocations by the North.
The Korean peninsula was devastated by a three-year civil war in the early 1950's. A truce agreement has been in effect for 60 years. But North Korea declared effective March 11 that it considered the armistice void.
U.S., South Korean and U.N. officials say the cease-fire pact cannot be abrogated unilaterally and consider that the 1953 armistice is still valid.