The powerful sister of Kim Jong-un had warned the United States to prepare for self-defence because North Korea is enhancing the destructive capability of its nuclear weapons on a day when the launch of other missiles heightened tensions in the Asia-Pacific area.
The Japan Coast Guard announced Monday morning that North Korea had launched three other ballistic missiles at Japanese waters. That followed the weekend launch of the Hwasong-15 intercontinental ballistic missile (ICBM) by Pyongyang's military.
This test prompted the United States to launch its long-range supersonic bombers alongside South Korean and Japanese warplanes in a show of force.
Kim Yo-jong, the sister of the Chairman of North Korea and deputy department director of the Central Committee of the Workers' Party of Korea, warned Washington that Pyongyang will respond to any "direct or indirect threat."
"The frequency of using the Pacific as our firing range depends upon the US forces' action," read a statement from the essential woman, who is regarded as a potential successor to her older brother.
"We affirm once again that there is no change in our will to make the worst maniacs escalating the tensions pay the price for their action."
She denied claims that the ICBM warhead's reentry had failed and emphasized that the weapons represented a threat to the United States. ICMBs might theoretically travel as far as North America.
"Such argument, made by those rookies who lack common sense and pretend to be experts, will not change the crisis facing the US and South Korea," said Kim Yo-jong.
"We possessed adequate technology and capability and will now concentrate on expanding their force size.
Instead of questioning or worrying about the technology of others, they should utilize their intelligence to devise defensive measures.
Monday's missile launch is the third significant weapons test conducted by the hermit nation this year. Pyongyang launched missiles on more than 30 occasions in 2022, including in March when it showed what was believed to be the world's most giant intercontinental ballistic missile (ICBM) test with a weapon that reached an altitude of more than 6,000 km and a range of about 1,100 km before falling within Japan's exclusive economic zone (EEZ).
Saturday, according to North Korea's state news agency, a Hwasong-15 missile flew as high as 5,768 kilometres before reaching a target region 989 kilometres away in open water.
Saturday at the Munich Security Conference, South Korean Foreign Minister Park Jin stated, "If North Korea conducts the seventh nuclear test, which could happen at any time, it will be a game changer in the sense that North Korea could develop and deploy tactical nuclear missiles."