(ATTN: RECASTS headline, lead to clarify the content)
SEOUL, Oct. 10 (Yonhap) -- North Korean hackers are believed to have stolen a large amount of classified military documents, including the latest South Korea-U.S. wartime operational plan, last year, a ruling party lawmaker said Tuesday.
Citing reports from the defense ministry, Democratic Party Rep. Rhee Cheol-hee said that the hackers broke into the Defense Integrated Data Center in September last year to steal the secret files, such as Operational Plans 5015 and 3100.
OPLAN 5015 is the latest Seoul-Washington scheme to handle an all-out war with Pyongyang, which reportedly contains detailed procedures to "decapitate" the North Korean leadership. OPLAN 3100 is Seoul's plan to respond to the North's localized provocations.
Rhee said that 235 gigabytes of military documents were taken with the content of nearly 80 percent of them yet to be identified. Also among them were contingency plans for the South's special forces, reports to allies' top commanders, and information on key military facilities and power plants, he added.
In May, the defense ministry's investigation authorities said that the communist state was thought to be behind the hacking of the military's key online network. They did not reveal what data had been taken at the time.
The hacking incident has raised calls for the allies to remain alert to the possibility of the belligerent regime readjusting its own contingency or wartime plans based on the stolen military documents.
In recent years, Seoul has been pushing to bolster its cyber defense capabilities as Pyongyang has launched a host of attacks on South Korean corporate and government websites by mobilizing its specially trained personnel, including those based in China and other foreign countries.
Pyongyang has denied responsibility for the cyberattacks, including the latest one, upbraiding Seoul for "fabricating" claims about online attacks.
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