Rhee, who belongs to the ruling Democratic Party and sits on the Defense Committee, told CNN on Tuesday that he received information about the alleged hacking from the Defense Ministry.
He said the documents stolen included the South Korea-US wartime operational plan and a document that includes procedures to “decapitate” the North Korean leadership.
About 235 gigabytes worth of military data was stolen by the hackers, Rhee said.
When asked about Rhee’s comments by reporters at a daily press briefing on Tuesday, a spokesman from South Korea’s Defense Ministry declined to comment, saying the information is classified.
The Pentagon also declined to comment specifically on reports of the potential breach, but spokesman Col. Robert Manning said on Tuesday that the US is “confident in the security of our operations plans and our ability to deal with any threat from North Korea.”
“The operations plan that they are referring to is a bilateral plan, so the Republic of Korea-US alliance remains steadfast in their commitment to make sure they safeguard that information and ensure readiness on the Korean peninsula to counter any North Korean threats,” Manning said.
“I’m not going to address the specifics of that discussion but what I will tell you is that it is a ROK-US alliance commitment to make sure that they safeguard operations and plans,” he added.