"I think it's increasing every day, which means that.we are in a race to be able to solve this problem", he said at a forum on Saturday.
It was the country's third intercontinental ballistic missile (ICBM) test, but the first of what North Korea is calling its Hwasong-15 missile.
An intercontinental ballistic missile that North Korea said could reach the "whole" mainland of the United States likely broke up upon re-entry into Earth's atmosphere, a USA official said Saturday.
The piece - which came shortly after Kim Jong Un enjoyed a visit to a military tyre factory - added: "The US and South Korean puppet warmongers would be well advised to bear in mind that their DPRK-targeted military drill will be as foolish as an act precipitating their self-destruction".
Republican U.S. Senator Lindsey Graham on Sunday urged the Pentagon to start moving U.S. military dependents, such as spouses and children, out of South Korea, saying conflict with North Korea is getting close.
"What matters is the fact that the drill simulating an actual war is to be staged at a time when insane President Trump is running wild", a commentary carried by the official Korean Central News Agency said.
North Korea: US 'begging' for war with 'largest ever' joint aerial drill
Russian Federation and China have proposed a roadmap for defusing the crisis in the region.
North Korea has repeatedly rejected accusations of human rights abuses and blames sanctions for a dire humanitarian situation. It has been set up under the South Korean army's Special Warfare Command.
Since fleeing the isolated empire in 2010, she said she has suffered chronic pain as a result of living near North Korea's Punggye-ri nuclear testing site.
The fifth-generation, single-seat, twin-engine, all-weather stealth tactical fighter aircraft will take part in the "Vigilant ace" exercise with the South Korean air force from December 4 to 8. The United States has been trying to get other countries, especially China, to squeeze North Korea's economy to make Kim back down from developing his country's nuclear weapons program.
Western analysts said it is more likely the truck was one of about half a dozen vehicles obtained years ago from China, which North Korea has modified since then.
It is likely the ballistic missile, fired higher than any previous North Korean missile, broke up as it re-entered Earth's atmosphere, the official said.