The Joint Chiefs of Staff (JCS) has rebuffed a request from the National Assembly to share details of a new joint wartime operational plan between Seoul and Washington, dubbed Operation Plan (OPLAN) 5015.
There have been media reports that the two allies created the new wartime plan in an apparent bid to address growing concerns over North Korea's evolving nuclear capability and its weapons of mass destruction (WMD).
The military is now looking into the leak of such confidential information at the request of the United States Forces Korea, which is worried that the new plan could provoke North Korea.
The Assembly has asked the JCS to share details of the plan; however, the latter refused to do so.
According to reports, former JCS Chairman Choi Yoon-hee and U.S. Forces Korea Commander Gen. Curtis Scaparrotti reportedly signed OPLAN 5015 in June to replace the existing OPLAN 5027.
The former is focused on preemptive strikes on strategic places in North Korea, including its nuclear and missile facilities, in the event of war, while the latter is about how to defend the country.
Last month, the JCS vowed to make a report of the new operational plan to a National Assembly session scheduled for Oct. 2. This was later put off until Oct. 5, but the JCS did not report details of OPLAN 5015, according to the Ministry of National Defense.
The JCS cited security reasons for not being able to release the details, but lawmakers claim that they have the right to know, as they have authority to approve the relevant budget.
During a confirmation hearing of the new JCS Chairman Lee Sun-jin on Oct. 5, lawmakers called on him to make a report in the near future.
Lee answered: "There is a regulation and law regarding maintaining security of the operational plan. I will review them after I am officially appointed."
He was appointed Wednesday.
The defense ministry and the JCS have remained silent about OPLAN 5015, saying that the details are categorized as confidential.
But defense watchers feel that the JCS's confusion about making a report to the Assembly or not seems to be because USFK Commander Scaparrotti strongly complained to Choi about media reports on the new plan.
Following the complaint from the USFK, the Defense Security Command is conducting an investigation into who leaked the information.
Allies are planning to conduct joint drills based on OPLAN 5015 from 2017, according to the sources.
OPLAN 5027 was known to stipulate that the U.S. would dispatch 690,000 personnel and mobilize 160 military vessels and 2,500 aircraft within 90 days of the outbreak of a war on the Korean Peninsula. Allies will concentrate on defense until these forces were deployed, and then advance northward. This plan raised the likelihood that the South would be seriously damaged while waiting for Washington's support.
"As far as I know, the new plan seeks for a victory in the early stage to keep war damage in the South to a minimum," a source said.
Sources noted that the new plan is aimed at ending the war as soon as possible through pinpoint strikes against the North's leadership including the young leader Kim Jong-un who can make the decision to use nuclear weapons.
OPLAN 5027 also included a concept of preemptive strikes when there is a clear sign of the North's firing of ballistic missiles, but OPLAN 5015 reportedly takes a more aggressive approach regarding this.
The new plan also includes detailed procedures for the allies to handle the North's regional provocation as well as all-out war.
Japan's Asahi Shimbun reported Monday that OPLAN 5015 focuses on regional and guerilla warfare.
Seoul and Washington have worked on drawing up OPLAN 5015 from 2007 in preparation for South Korea's takeover of wartime operational control (OPCON) of its troops from the U.S., originally scheduled for the end of 2015. The initial concept was that South Korean armed forces would lead operations, and the U.S. would back them up.
However, this concept was modified to ROK-U.S. Combined Forces Command (CFC) leading operations, as in the existing OPLAN 5027, following a decision of the two countries' defense chiefs in October of last year to delay the transition of wartime OPCON until South Korea's military capability against nuclear and missile threats from Pyongyang was secure. At the time, the Ministry of National Defense noted that the transition could take place in the mid-2020s.
Follow Jun Ji-hye on Twitter @TheKopJihye