The United States says it’s taking "all necessary precautions" after North Korea rang fresh alarms in an escalating crisis by moving a medium-range missile to its east coast.
South Korea says the missile could reach a "considerable distance" but not the US mainland.
Pyongyang has renewed threats of a nuclear strike against the US, though its missiles are not believed to be capable of carrying nuclear warheads.
White House spokesman Jay Carney said the barrage of threats fitted a "regrettable but familiar" pattern of North Korean behaviour.
But Jim Walsh, an International Security Analyst, believes the nature of these threats is different to previous ones.