North Korea’s leader Kim Jong-un ordered the military to prepare for missile strikes against American bases in South Korea and the Pacific Ocean on Friday, a day after the United States flew two strategic stealth bombers over the Korean Peninsula in a show of force.

State news media reported that Kim “judged the time has come to settle accounts with the American imperialists” and that hostilities between the two countries can only be settled by “physical means.”

North Korea has taken increasingly provocative, if sometimes symbolic, steps in recent weeks, including the suspension of a military hotline with the South. “Under the situation where a war may break out any moment, there is no need to keep North-South military communications,” it argued.

On Monday, North Korea’s army command complained that “the United States’ nuclear threats and blackmail” were “turning into actual war moves” and it announced that it would demonstrate its resolve “through actual military action.” That seems to have referred to an increase in its combat readiness to the highest level.

As a result, artillery and missiles north of the demilitarized zone that separate the communist state from the democratic South should now be able to respond to an attack or launch a preemptive strike within minutes of the order being given from Pyongyang. Yet such an assault would require massive retaliation from South Korea and the United States, effectively crippling the impoverished dictatorship.

Tension has been high since the North conducted a nuclear weapons test in February, its third and in breach of United Nations sanctions. China, its only ally, unusually said it was “strongly dissatisfied” by the test and would not block tougher sanctions against North Korea in the United Nations Security Council.

The North subsequently canceled the armistice agreement that ended the Korean War in 1953 — although it has announced five time before that it would no longer abide by that ceasefire.

Despite recent threats, North Korea continues to operate a joint economic zone with the South in Kaesŏng that generates some $2 billion in trade per year.