North Korea on Tuesday claimed it successfully test-launched its first intercontinental ballistic missile, a potential game-changing development in what may be the world's most dangerous nuclear standoff and, if true, a direct rebuke to U.S. President Donald Trump's earlier declaration that such a test "won't happen!" North Korea's Academy of Defense Science said the test of an ICBM — the Hwasong-14 — marked the "final step" in creating a "confident and powerful nuclear state that can strike anywhere on Earth."