SEOUL, South Korea — South Korea said Tuesday that 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 its earlier estimate that the North had a cyberwarfare staff of 3,000.

Seoul's Defense Ministry said in a report that North Korea may also have gained the ability to strike the U.S. mainland because of its recent progress in missile technology, which was demonstrated in five long-range missile tests in 2009 and 2012, 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, Kim Jong Un. North Korea has denied any involvement in the breach of tens of thousands of confidential Sony emails and business files.

Former South Korean Defense Minister Kim Kwan-jin said in 2013 that North Korea was operating a cyberwarfare staff of 3,000. South Korea accuses North Korea of conducting at least six high-profile cyberattacks since 2007 and many more unsuccessful attempts to infiltrate computer systems of businesses and government agencies.

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.