[Yang Nak-gyu's Defence Club] Movement in Tunnel No. 4... South Korea and US on Alert

[Image source=Yonhap News] U2 Landing (Pyeongtaek=Yonhap News) Reporter Kim In-cheol = On the afternoon of the 29th, when North Korea launched an intermediate-range ballistic missile (IRBM) that passed over Japanese airspace and fell into the North Pacific, a U2 high-altitude reconnaissance aircraft was landing after completing its mission at Osan Air Base, home to the US Forces Korea in Pyeongtaek, Gyeonggi Province. 2017.8.29 Photo by Kim In-cheol yatoya@yna.co.kr (End)

[Asia Economy Yang Nak-gyu, Military Specialist Reporter] As North Korea continues to show signs of a 7th nuclear test, South Korean and U.S. military authorities are on high alert. This is because movements have been detected not only at Tunnel No. 3 but also at Tunnel No. 4 of the Punggye-ri nuclear test site in Kilju County, North Hamgyong Province, North Korea.

The North Korea-focused website "Beyond Parallel," operated by the U.S. Center for Strategic and International Studies (CSIS), analyzed satellite images taken on the 14th and reported that construction work such as the installation of concrete barriers is underway around the entrance of Tunnel No. 4 within the nuclear test site.

Tunnel No. 4 at the Punggye-ri nuclear test site has never been used. Tunnel No. 1 was closed after the first nuclear test in 2006, and tunnels No. 2 were used for the 2nd to 6th nuclear tests from 2009 to 2017. However, North Korea announced in May 2018 that tunnels No. 3 and No. 4 were closed by "detonation" methods.

Our military authorities only explained, "South Korean and U.S. intelligence agencies are closely tracking and monitoring nuclear-related facilities and activities under tight cooperation and maintaining a firm readiness posture." It is unusual that the military used the term "activities."

With the reappearance of "unusual movements" at the Punggye-ri nuclear test site, South Korean and U.S. authorities are paying close attention.

Our military has strengthened reconnaissance missions using aircraft such as Geumgang and Baekdu (RC-800), and Saemae (RF-16). Geumgang and Saemae have been collecting video intelligence from the area connecting Nampo to Hamhung in North Korea, while Baekdu has been gathering signals intelligence including electronic intelligence (Elint) and communications intelligence (Comint). Geumgang and Baekdu (RC-800) are deployed at the Air Force's 15th Fighter Wing, and Saemae reconnaissance aircraft are assigned to the Air Force's 19th Fighter Wing.

The U.S. military is flying over the Korean Peninsula daily using RC-12X "Guardrail" and RC-135V "Rivet Joint" aircraft. On the 16th, the U.S. also deployed the B-52H long-range bomber, a representative strategic asset capable of carrying nuclear missiles. The B-52H can carry 12 AGM-129 cruise missiles and 20 AGM-86A cruise missiles equipped with nuclear warheads, as well as air-to-ship missiles, conventional bombs, and a total of 32 tons of weapons. Previously, the B-52H conducted a show-of-force flight over Japanese airspace on the 25th of last month during North Korea's ICBM (intercontinental ballistic missile) launch.

This was interpreted as a warning message to North Korea, supporting the "strengthening of extended deterrence capabilities" agreed upon at last month's South Korea-U.S. summit.

The B-1B strategic bomber squadron has been on standby in Guam for over ten days. Satellite images taken on the 15th of the Guam base area captured four B-1B bombers, according to the Voice of America (VOA). The B-1B squadron, belonging to Ellsworth Air Force Base, was forward-deployed to the Guam base on the 3rd.

This content was produced with the assistance of AI translation services.