SEOUL — North Korea could be behind a computer hacking incident that gave the rogue government access to a summary of what the militaries of South Korea and the United States plan to do in the event war would resume on the peninsula.

“We strongly believe that it is North Korea’s act,” a spokesman for the South Korean Joint Chiefs of Staff said Friday. The spokesman said it was too early in South Korea’s investigation, however, to be certain that Pyongyang was responsible for the cyber attack.

It is also unclear what, if anything, North Korea could do with the stolen information if the regime does have it, the spokesman said.

United States Forces Korea spokesman David Oten declined to comment on the hacking report, saying it is the command’s policy not to discuss details of intelligence matters or any possible security investigations. Attempts to contact a spokesman for the U.S. Embassy in South Korea late Friday were unsuccessful.

South Korea Defense Ministry spokesman Won Tae-jae said the suspected hacking occurred in late November when a South Korean officer failed to remove a USB device when he switched a military computer from a restricted-access intranet to the Internet, according to The Associated Press. The device contained an 11-page summary of military operations South Korea and the U.S. plan in the event hostilities would resume with North Korea. Won said the full text of the operational plans was not compromised, The Associated Press reported.

North and South Korea are technically still at war, as the hostilities of the Korean War were only suspended by an armistice in 1953, and no peace treaty was ever signed.

In July, hackers launched high-profile cyber attacks that caused Web outages on prominent government-run sites in the U.S. and South Korea. Affected sites included those of the White House and South Korea’s presidential Blue House.

The Internet Protocol address that triggered those Web attacks was traced back to North Korea’s Ministry of Post and Telecommunications, the chief of South Korean’s main spy agency reportedly told lawmakers, according to AP.

South Korean media outlets have reported that North Korea runs an Internet warfare unit that tries to hack into U.S. and South Korean military networks to gather confidential information and disrupt service, and the regime has between 500 and 1,000 hacking specialists, according to AP.

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