The Soviet Union actively aided the North Korean military. When the Soviet occupation troops withdrew in December 1948, they left behind as many as 150 advisors in each KPA division for training and organizational purposes. Under the terms of a reciprocal aid agreement concluded on 17 March 1949, the Soviets agreed to furnish North Korea with arms and equipment for six infantry divisions, three mechanized units, and eight battalions of mobile border constabulary. During 1949–1950, the Soviet Union supplied 10 reconnaissance aircraft, 100 Yak fighter planes, 70 attack bombers, and 150 Russian T-34 and T-70 tanks as well as heavy artillery. The North Korean armed forces were thus far superior to the Republic of Korea's (ROK, South Korea) army in training, manpower, firepower, and equipment when North Korea invaded South Korea on 25 June 1950.
The KPA was decimated by the U.S.-led United Nations (UN) forces in the early stages of the Korean War. During the war, North Korean armed forces suffered horrendous casualties totaling 294,151 dead and 229,249 wounded. At the end of the conflict, the KPA was less than half the strength of the South Korean armed forces.
After the war, North Korea pursued military augmentation. Kim Il Sung took a militant posture toward South Korea and the United States, increasing defense expenditures at the expense of economic development. The North Korean armed forces are now estimated to number some 1.2 million people, the fifth-largest military establishment in the world. Following the philosophy of Juche (self-reliance), North Korea has developed an extensive defense industrial capacity, although most of its equipment is of outdated Soviet or Chinese design. Some equipment has been redesigned by North Koreans, however, including armored personnel carriers, self-propelled artillery, light tanks, high-speed landing craft, Romeo-class submarines, SCUD-derived surface-to-surface missiles, and antitank missiles (the SA-7, SA-14, SA-16, and possibly SA-2). Aircraft production is believed to have begun in 1995. North Korea operates some 134 armament factories, many of them underground.
The large number of North Korean troops and equipment poses a grave threat to South Korea. North Korean ground forces are composed of 20 corps with 170 divisions and brigades, including 25 SOF (Special Operations Forces) brigades. North Korea has deployed approximately 10 corps and some 60 divisions and brigades in the forward area south of the Pyongyang/Wonsan line and is thus prepared to launch a surprise attack and invade South Korea without further troop deployment. North Korea has some 3,800 tanks, 2,300 armored vehicles, 12,500 artillery, and 13,800 air defense weapons. North Korea has more fighters and bombers than South Korea, but the equipment is old. The North Korean Air Force has 790 fighters, 80 bombers, 520 support aircraft, and 320 helicopters. MiG-19s and MiG-21s make up the core of the aircraft. North Korea is also equipped with some highly advanced fighters such as the MiG-23 and MiG-29 as well as the SU-25. North Korea built underground facilities to store and protect its combat aircraft. Ninety submarines, of which some 70 are coastal or midget craft, form the main component of the North Korean Navy.
The North Korean government has had the desire and capability to develop nuclear weapons, build and export medium-range missiles, and construct and stockpile chemical and biological weapons. It has exerted full effort in nuclear development since the 1950s, receiving technological support from the former Soviet Union. It is estimated that by the 1990s, North Korea acquired sufficient weapons-grade plutonium to make one or two nuclear bombs. Eight different factories in North Korea have produced lethal chemicals such as nerve, blister, and blood agents as well as tear gas. Their quantity is estimated to be 2,500–5,000 tons. North Korea is also suspected of maintaining numerous facilities for cultivating and producing anthrax and other forms of biological weapons. Since the early 1980s, North Korea has also embarked on the development of ballistic missiles and has already produced and deployed 500km-range SCUD-Cs by upgrading Soviet SCUD-Bs. In 1993, North Korea succeeded in test-firing a 1,300km-range Nodong-I missile and has deployed the missiles for operational purposes since 1997. The maximum ranges of long-range Taepodong-I and Taepodong-II missiles are estimated to reach 2,000–2,500 kilometers and 6,700 kilometers, respectively.
Pyongyang has pursued a military-first policy, and its armed force has been the pillar of the so-called socialist revolution and the main force for its Juche philosophy. As a result of the steady increase in military manpower and weaponry, North Korea has essentially become one huge armed camp. It is the most heavily armed nation in the world, relative to its size. But the government's efforts to build a powerful military force have greatly taxed the North Korean economy. About 25 percent of its gross national product (GNP) has been allocated to the maintenance of its armed force. Such an emphasis has had seriously adverse effects on the nation's standard of living. Since the Soviet Union finally collapsed in 1991, North Korea has had serious problems and has become increasingly isolated internationally. The North Korean armed forces remain potent, but it is unclear how long they can continue to prop up such a repressive regime.
Minnich, James M. The North Korean People's Army: Origins and Current Tactics. Annapolis, MD: Naval Institute Press, 2005.; Republic of Korea Ministry of National Defense. "Defense Data and Statistics, 2001." Seoul: December 2001.