Kim, announcing the second intercontinental ballistic missile (ICBM) test, said it demonstrated that North Korea could launch "at any place and time." The KCNA also quoted him as saying that "the test confirmed all the US mainland is within our striking range."
But should these claims be taken seriously? Can North Korean ICBMs really strike any target in the US? After all, North Korean leaders are known for exaggerating their nuclear and missile program achievements.
Standard trajectory and altitude
But it seems that Pyongyang is not entirely incorrect about its ICMB claims.
Military analysts say the latest North Korean ballistic missile appeared to have a range of around 10,000 kilometers (6,200 miles), which would put the US mainland within its reach.
"Based on current information, today's missile test by North Korea could easily reach the US West Coast, and a number of major US cities," arms expert David Wright of the Union of Concerned Scientists said on his blog.
Los Angeles, Denver and Chicago appear to be well within range of the ICBM, which may also be capable of hitting Boston and New York, Wright said.
North Korean officials said the latest missile had flown for 47 minutes and reached an altitude of more than 3,700 kilometers. On a standard trajectory, the missile would have a range of 10,400 kilometers.
Earth's rotation boosts range
According to the Union of Concerned Scientists, North Korea launched its missile on a high trajectory to allow it to fall into the Sea of Japan rather than fly over Japan. However, it was still possible to calculate the range.
If fired eastward, the rotation of the Earth could also increase the range of the missile, meaning the missiles have different ranges depending on the direction they are fired in.
Los Angeles is at a distance of 9,500 kilometers from North Korea, and the calculated range of the missile toward the city is 11,700 kilometers, according to the Union of Concerned Scientists. If fired in the direction of Boston, the missile range would be 10,750 kilometers - still just about enough to reach the city.
New York would also be roughly in range, but Washington DC would probably be just outside the strike area.
The organization stressed that the missile range also depends on the mass of the payload it carries. A heavier payload than that used in the test flight might mean the range would be reduced.