[PopularMechanics] Units of the U.S. Army are training to map out, and if necessary fight in, North Korea’s underground complexes. Soldiers from the Army’s 1st Cavalry Division are training in underground tunnels to prepare for the mission of securing North Korean tunnels in the event of war. North Korea is estimated to have thousands of tunnels and underground facilities that would shelter the regime leadership and possibly chemical and nuclear weapons, in the event of war with the United States and South Korea.During the four day exercise described by Stars and Stripes, dubbed Warrior Strike IX, troops from the 1st Battalion, 5th Cavalry regiment, 1st Cavalry Division practiced breaching and entering tunnel complexes at the U.S. Army’s Camp Stanley in South Korea. The soldiers conducted the exercise wearing chemical protective suits and night vision goggles to see in the dark.
North Korea is estimated to have between 6,000 and 8,000 underground facilities. Meant to preserve the country’s leadership and armed forces from air attack, the facilities are also thought to store stockpiles of chemical weapons. In 2012, South Korea estimated the North had between 2,500 and 5,000 metric tons of chemical arms, including mustard gas, hydrogen cyanide, and highly lethal nerve agents including sarin, soman, and VX. In 2017, North Korean agents assassinated leader Kim Jong-un’s half brother in Malaysia with a lethal dose of VX, making it seem even more likely the country might use such weapons in wartime.
Stars and Stripes, reporting on the exercise, says the soldiers negotiated a half-mile long horseshoe-shaped tunnel equipped with the Mobile Ad Hoc Networking Unit system, or MPU5. Described by the manufacturer as the "World’s First Smart Radio," it creates a peer-to-peer wireless relay network capable of relaying signals from deep underground to the surface. MPU5 is based on the Android OS and can handle voice, data, and video. The device was also linked to trackers attached to soldiers’ boots, like horseback riding spurs, allowing the Army to keep track of troops underground.
In the event of war on the Korean peninsula South Korean soldiers will do the bulk of the fighting, both above and underground. Still U.S. forces would likley do a considerable amount themselves, and must be ready to fight and communicate hundreds of feet underground in the dark. In the meantime, U.S. troops must train for every contingency .