A full-blown North Korean attack is unlikely, though there are fears of a more localized conflict, such as a naval skirmish in disputed Yellow Sea waters.
Such naval clashes have happened three times since 1999.
North Korea's threats are seen by outside analysts as efforts to provoke South Korea to soften its policies and to win direct talks with Washington that could result in aid. Kim's comments are also seen as ways to build domestic loyalty and strengthen his military credentials.
Kim “convened an urgent operation meeting” early Friday, signed a rocket preparation plan and ordered his forces on standby to strike the U.S. mainland, South Korea, Guam and Hawaii, state media reported.