Experts say the North Koreans must conduct further tests of its atomic devices and make them smaller before they can be mounted as nuclear warheads onto long-range missiles.
Though it insists its efforts to launch a satellite are peaceful, North Korea also claims the right to build nuclear weapons as a defense against the United States, which stations more than 28,000 troops in South Korea. The adversaries fought in the three-year Korean War, which ended in a truce in 1953 and left the Korean Peninsula divided by the world's most heavily fortified demilitarized zone.
North Korea has enough weaponized plutonium for about four to eight bombs, according to nuclear scientist Siegfried Hecker, who visited North Korea's nuclear complex in 2010. In 2009, Pyongyang also declared that it would begin enriching uranium, which would give North Korea a second way to make atomic weapons.