North Korea cannot 'tip' missile with nuclear warhead - U.S. State Department

North Korea continues to pursue nuclear and ballistic missile technologies but the United States does not believe it is in a position to "tip" one of them with a nuclear warhead, State Department spokesman John Kirby said on Tuesday. North Korea's leader, Kim Jong Un, said on Sunday his nuclear-capable country was close to test-launching an intercontinental ballistic missile (ICBM), raising the prospect of putting parts of the United States within range.