North Korea said it is placing its military on high alert on Tuesday. It warned the United States of “disastrous consequences” it would face for having sent an aircraft carrier and other warships into a South Korean port.

“[T]he units of all services and army corps level of the [North Korean army] received an emergency order from its supreme command to … keep themselves fully ready to promptly launch operations anytime … The U.S. will be wholly accountable for the unexpected horrible disaster to be met by its imperialist aggression forces’ nuclear strike means,” a spokesman for the army wrote on North Korea’s state-run news agency website.

This is only the latest in a string of threats North Korea has issued against the United States and South Korea.

Back in March, Pyongyang declared that it had nullified the 1953 truce that ended the Korean War, saying, “The U.S. has reduced the armistice agreement to a dead paper” by holding joint military drills with South Korea.

The North has repeatedly defied international laws banning development of its long-range and nuclear missiles, and experts believe the North now has the capacity to build as many as 10 nuclear bombs.

After the death of Kim Jong-il in December 2011, his son Kim Jong-un took up the reins of North Korea. Many analysts thought the transition would trigger a reversal in the country’s rogue behavior. After all, the young Kim Jong-un had received a Western education, and was an outspoken fan of Michael Jordan and James Bond films. Optimistic westerners said that what little information was available about Jong-un suggested that he might abandon the internal oppression and external belligerency that had marked the reigns of his father and grandfather.

But Jong-un is desperate to prove himself worthy to his nation’s hard-line military, and it is now clear that, under his rule, nuclear North Korea is more aggressive, more unpredictable and more dangerous than ever.

In February, Pyongyang conducted its third nuclear weapons test, prompting the United Nations to impose new sanctions on it. The North responded by threatening preemptive nuclear attacks on South Korea and the U.S.

“If we push the button, they will blast off and their barrage will turn Washington, the stronghold of American imperialists and the nest of evil … into a sea of fire,” Vice Defense Minister Kang Pyo-yang said.

But would the North actually attempt any attacks with its relatively primitive weaponry?

After the threat, Congressman Mike Rogers said the threats are not empty bluster: “They certainly have a ballistic missile that can reach U.S. shores. You have a 28-year-old leader who is trying to prove himself to the military, and the military is eager to have a saber-rattling for their own self-interest, and the combination of that is proving to be very, very deadly.”

Recent history has also taught the North that, shy of sanctions, there is no reason not to provoke U.S. allies. In 2010, a North Korean submarine sunk a South Korean vessel, killing 46 sailors. Later that year, troops from the North killed four South Koreans with an artillery barrage. Pyongyang was only slapped on the wrist for those incidents. It’s no surprise that its leaders believe they can antagonize again without retaliation from the U.S.

Although North Korean threats rarely materialize into action, they show the world that the U.S. is a broken-willed nation that can be threatened and antagonized without consequence. America’s tolerance of Pyongyang’s provocative bluster may signal to Iran, Russia and other enemies of the West that they too can get away with aggression and provocations.

Asia’s rising tensions point to dark times on the horizon. To understand more, read Russia and China in Prophecy.