North Korea hackers stole South Korea-U.S. military plans - Yonhap

North Korean hackers may have stolen a large amount of classified military documents, including the latest South Korea-U.S. wartime operational plan, a South Korean ruling party lawmaker said, Yonhap News reported on Tuesday.

Democratic Party representative Rhee Cheol-hee said 235 gigabytes of military documents were taken from the Defense Integrated Data Center, citing information from unnamed defence officials, Yonhap News reported.

The contents of about 80 percent of the data have not yet been identified, Yonhap reported, citing Rhee, adding that the hack took place in September last year.

Pyongyang has denied responsibility for the cyberattacks, Yonhap reported, criticizing Seoul for "fabricating" claims about online attacks.

Neither Rhee Cheol-hee, nor his office, were immediately available for a comment.

In Washington, the Pentagon said it was aware of the media reports but would not comment on the potential breach.

"Although I will not comment on intelligence matters or specific incidents related to cyber intrusion, I can assure you that we are confident in the security of our operations plans and our ability to deal with any threat from North Korea," Pentagon spokesman Colonel Robert Manning told reporters.