South Korea says rival North Korea has a 6,000-member cyber army dedicated to disrupting the South's military and government. The figure is a dramatic increase from South Korea's earlier estimate that the North had a cyberwarfare staff of 3,000.

Seoul's Defense Ministry also said in a report Tuesday that North Korea may now have the ability to strike the U.S. mainland because of its recent progress in missile technology and is advancing in efforts to miniaturize nuclear warheads to mount on such missiles.

The United States accuses North Korea of a cyberattack on Sony Pictures over a movie depicting the fictional assassination of the North's leader.

The Korean Peninsula is still in a technical state of war because the 1950-53 Korean War ended in an armistice, not a peace treaty.