Washington (CNN) A North Korean official reaffirmed Pyongyang's commitment to developing a long-range intercontinental ballistic missile capable of reaching "all the way to the East coast of the mainland US," on Monday, telling CNN that the rogue nation is currently not interested in diplomacy with the US until it achieves that goal. 
 
 The comments offer a sobering challenge to the US and the Trump administration which has offered mixed messages regarding diplomatic efforts with North Korea. 
 
 White House chief of staff John Kelly said last week that Americans should be concerned about North Korea's ability to reach the United States with an intercontinental ballistic missile, cryptically telling reporters that if the threat grows "beyond where it is today, well, let's hope that diplomacy works." 
 
 Significantly, Kelly noted that Pyongyang "is developing a pretty good nuclear re-entry vehicle." 
 
 For a missile to successfully strike a target it would have to re-enter the earth's atmosphere without breaking up. 
 
 Kelly's comments seem to indicate that the US believes that North Korea is close to achieving what would be a key breakthrough for their missile program. 
 
 The North Korean official told CNN that two additional steps are needed to achieve its goal of a reliable ICBM. 
 
 One step is an above-ground nuclear detonation , like the kind North Korean Foreign Minister Ri Yong Ho threatened at the United Nations last month when he suggested leader Kim Jong Un was considering detonating "an unprecedented scale hydrogen bomb " over the Pacific after Trump threatened to "totally destroy" North Korea. 
 
 The other step is the "testing of a long-range ICBM capable of reaching Guam - and even further," the official said. 
 
 Last week, North Korean state media renewed a threat to launch missiles toward the US territory of Guam, warning that "reckless moves" by the US would compel Pyongyang to take action. 
 
 North Korea first said it was examining a plan to target the Pacific island in August after Trump warned the isolated regime would "face fire and fury like the world has never seen" following a US intelligence assessment that North Korea had produced a miniaturized nuclear warhead. 
 
 Both steps are necessary for the DPRK to send that "clear message" to the Trump administration that it possesses an effective nuclear deterrent, the North Korean official said on Monday. 
 
 The official added that one or both of these tests could possibly be timed to coincide with the US-South Korea joint naval drills, which began Monday and will last for ten days, or could possibly coincide with Trump's visit to Asia next month. 
 
 Joint military exercises are particularly infuriating to Pyongyang. The North Korean government views them as a dress rehearsal for an invasion -- even as the US insists they are purely defensive in nature. 
 
 The US will practice evacuating civilians from South Korea in its annual Courageous Channel training exercise later this month -- a routinely scheduled exercise that "prepares service members and their families to respond to a wide range of crisis management events such as non-combatant evacuation and natural or man made disasters," according to US Forces Korea. 
 
 Asked Monday if his possible visit to the Korean Demilitarized Zone (DMZ) next month will provoke North Korea Trump said he would "take a look at that" but added he "hadn't heard in terms of provoking." 
 
 On Sunday, US Secretary of State Rex Tillerson said his diplomatic efforts will continue as long as they possibly can despite the saber-rattling on both sides of the Pacific. 
 
 "Those diplomatic efforts will continue until the first bomb drops," Tillerson said on CNN's "State of the Union." 
 
 Democratic Rep. Brendan Boyle of the House Foreign Affairs Committee told CNN's Wolf Blitzer on Monday that he believes the US should continue to pursue diplomacy with Pyongyang but ultimately, must prevent North Korea from developing a nuclear weapon capable of reaching the US. 
 
 "I don't believe we can live with that possibility," he said. 
 
 North Korean anger over US 'decapitation' plan 
 
 A North Korean diplomat publicly expressed anger on Monday over reports that hackers gained access to a US-South Korean plan to "decapitate" the regime's leadership. 
 
 North Korea's deputy UN Ambassador warned that the plan is "dangerous" and an insult to the nation. 
 
 CNN has reported that the North Korea hackers stole classified military documents from a South Korean Defense ministry database in September 2016, according to Rhee Cheol-hee, a member of South Korea's National Assembly. He said the documents stolen included the South Korea-US wartime operational plan and a document that includes procedures to "decapitate" the North Korean leadership. 
 
 North Korea's deputy Ambassador Kim In Ryong told a UN committee meeting on nuclear issues that "what is more dangerous is that the US dared to formulate a plan and stage the exercise of decapitation operation and secret operation aimed at the removal of our supreme leadership." 
 
 "This is an unbearable insult to the supreme dignity of the DPRK and it arouses extreme anger from our people and service personnel," Ryong said. 
 
 The North Korean UN diplomat also fiercely defended Pyongyang's nuclear and missile tests. 
 
 Why North Korea wants nukes and missiles North Korea has long maintained it wants nuclear weapons and long-range missiles to deter the United States from attempting to overthrow the regime of Kim Jong Un. Pyongyang looks at states such as Iraq -- where Saddam Hussein was overthrown by the United States -- and Libya -- its late leader, Moammar Gadhafi, gave up his nuclear ambitions for sanctions relief and aid, only to be toppled and killed after the United States intervened in his country's civil unrest -- and believes that only being able to threaten the US mainland with a retaliatory nuclear strike can stop American military intervention. Many experts say they believe North Korea would not use the weapons first. Kim values his regime's survival above all else and knows the use of a nuclear weapon would start a war he could not win, analysts say. 
 
 "Unless the hostile policy and the nuclear threat of the US is thoroughly eradicated, we will never put our nuclear weapons and ballistic rockets on the negotiation table under any circumstance and will never flinch even an inch from the road we have chosen, upholding the line of simultaneously developing the two fronts, the everlasting banner in safeguarding the peace," Ryong said. 
 
 "This year, we have passed the final gate of completing the state nuclear force and thus became the full- fledged nuclear power which possesses the delivery means of various ranges, including the atomic bomb, H-bomb and intercontinental ballistic rockets," he said. "The entire US mainland is within our firing range and if the US dares to invade our sacred territory even an inch it will not escape our severe punishment in any part of the globe." 
 
 Mixed messages 
 
 US-led efforts to apply additional diplomatic pressure on North Korea in recent months have been met with greater defiance as the Kim regime continues to march toward realizing its nuclear ambitions. 
 
 Despite assurances from Defense Secretary James Mattis and Secretary of State Rex Tillerson that the US continues to seek a peaceful resolution, neither side has overtly indicated that it is ready or willing to engage in serious negotiations. 
 
 Trump has repeatedly undercut comments made by his top officials and publicly engaged in a war of words with Kim that has devolved into insults and name-calling -- only raising fears of an eventual military conflict. 
 
 Trump said earlier this month that the US will "do what we must do" to prevent further threats from North Korea. 
 
 "We cannot allow this dictatorship to threaten our nation or our allies with unimaginable loss of life," he said at a meeting with top military officers. "We will do what we must do to prevent that from happening and it will be done if necessary, believe me." ||||| Leaders agreed to call for an emergency meeting of the UN security council to discuss the launch 
 
 Donald Trump and Shinzo Abe have vowed to increase pressure on North Korea after the regime launched a missile over Japan on Tuesday morning. 
 
 The Japanese prime minister denounced the launch as an “unprecedented and grave threat” to the country’s security. In a 40-minute phone call with the US president they agreed to call for an emergency meeting of the UN security council to discuss the situation. 
 
 
 
 Living on the edge of oblivion: life along the North Korean border Read more 
 
 Officials in South Korea said the missile may have flown further than any other tested by North Korea. The test, one of the most provocative ever from the reclusive state, sent a clear message to Washington just weeks after Kim Jong-un threatened to target the US Pacific territory of Guam with similar intermediate-range missiles. 
 
 It also demonstrated the regime’s willingness to raise the diplomatic stakes by sending a missile directly over Japanese territory. Pyongyang has tested more powerful intercontinental ballistic missiles (ICBM) this year, but Tuesday’s launch followed a much flatter trajectory than those tests. 
 
 Trump said the US was “100% with Japan” and repeated his strong commitment to the defence of Japan, Abe said shortly after the call. 
 
 
 
 “The outrageous act of firing a missile over our country is an unprecedented, serious and grave threat and greatly damages regional peace and security,” Abe told reporters in Tokyo, adding that his government had protested to Pyongyang via the Japanese embassy in Beijing. 
 
 The missile was the third fired by North Korea to have passed over Japanese territory. The first was in 1998 and the second in 2009, although Pyongyang claims they were satellites. 
 
 Abe said Japan would “strongly call for increased pressure on North Korea in cooperation with the international community” via the security council. 
 
 
 
 The missile, thought to be a new intermediate-range Hwasong-12, flew over Hokkaido and landed in the Pacific about 733 miles (1,180km) east of the northern Japanese island, South Korean and Japanese officials said. 
 
 The Hwasong-12 is the same type of missile North Korea recently threatened to launch towards Guam. 
 
 China called for restraint and warned that the situation on the Korean peninsular had reached “a tipping point approaching a crisis”. 
 
 Foreign ministry spokeswoman Hua Chunying told a daily press briefing in Beijing: “Think hard about it, who do you think should take the blame, if China is urging all parties to calm down while one party holds constant military exercises … and the other is constantly launching missiles?” 
 
 Japan’s J-Alert warning system advised people across a large area of northern Japan to seek shelter. Japan’s self-defence forces did not attempt to shoot down the missile and there were no reports of damage from falling debris. 
 
 
 
 The public broadcaster NHK said the missile had been launched from a site near the North Korean capital, Pyongyang and passed over a sparsely populated area of Hokkaido just after 6am local time (10pm Monday British summer time). It broke into three parts and landed in the sea. 
 
 Seoul’s joint chiefs of staff (JCS) said the missile travelled about 2,700km and reached a maximum height of 550km. 
 
 The JCS said it was analysing the launch with the US and that South Korea’s military had strengthened its monitoring and preparation in case of further actions from North Korea. 
 
 Abe said his government was trying to establish the details of the launch and was doing everything possible to ensure the safety of the Japanese people. 
 
 Tuesday’s launch may have been a show of defiance towards military drills involving US and South Korean troops as well as a smaller number of personnel from other countries. 
 
 The drills have coincided with a dramatic rise in tensions on the Korean peninsula after North Korea’s test launch of two ICBMs and its threat to target seas off the coast of the Guam. 
 
 Seoul and Washington say their drills are an opportunity for the allies to improve their defensive capabilities but Pyongyang routinely denounces them as a dress rehearsal for war against North Korea. 
 
 On Tuesday North Korea’s ambassador to the UN said the joint exercises were driving the Korean peninsula towards “an extreme level of explosion”. 
 
 “Now that the US has openly declared its hostile intention towards the Democratic People’s Republic of Korea, by waging aggressive joint military exercises despite repeated warnings … my country has every reason to respond with tough counter-measures as an exercise of its right to self defence,” Han Tae Song told the UN conference on disarmament, which is taking place in Geneva. 
 
 At the UN conference, multiple envoys, including those from the US, European Union, Japan and Australia took the floor to blast North Korea. “My hope is that North Korea ends this provocative behaviour,” US ambassador Robert Wood said. 
 
 Facebook Twitter Pinterest US soldiers during the annual US South Korea Ulchi-Freedom Guardian military exercises in Paju, South Korea, near the border with North Korea. Photograph: Ahn Young-joon/AP 
 
 
 
 
 
 The latest launch came three days after the North fired what were assessed as three short-range ballistic missiles into the sea and a month after its second test flight of an ICBM that analysts say could theoretically reach the US mainland. 
 
 Tuesday’s missile landed nowhere near Guam, which is about 2,500km south of Tokyo, but it covered enough distance to suggest that North Korea could follow up on its threat to the US territory. 
 
 South Korea said it was launched from Sunan, the location of Pyongyang’s international airport, raising the possibility that a runway was used as the launchpad. 
 
 Several towns in Japan have held evacuation drills this year in anticipation of a North Korean attack and there has been a steep rise in sales of individual nuclear shelters. 
 
 
 
 After North Korea threatened to fire a volley of missiles towards Guam earlier this month, Japan deployed Patriot missile defence systems in areas along the missiles’ anticipated route. Japan also has an Aegis destroyer stationed in the Sea of Japan. 
 
 North Korea first fired a missile over Japanese territory in 1998, triggering widespread condemnation and attempts by Japan’s government to improve its missile defence systems. 
 
 Japan has in the past vowed to shoot down North Korean missiles or rockets that threaten to hit its territory. In 2009 a North Korean rocket passed over Japanese territory without incident, leading to an immediate denunciation by Japan. 
 
 At the time North Korea said it was launching a telecommunications satellite but Washington, Seoul and Tokyo believed Pyongyang was testing an ICBM. 
 
 Wang Zhen in Beijing and agencies contributed to this report
– Pyongyang has a message for the US: North Korea has become a "fully-independent rocket and nuclear weapons state," according to an official website—and America "should be acutely aware that the US mainland is now well within the range of our strategic rockets and nuclear weapons." How credible is the warning? Experts say it could be awhile before the North actually has an intercontinental ballistic missile ready, AFP notes. But debris from December's rocket launch suggested its possible range included the US West Coast, according to South Korea. Closer to home, Pyongyang is fuming over planned US-South Korea military drills. The Korean peninsula is "an inch away from explosion," official news warns. "The US is to blame for the situation on the Korean peninsula, which is inching close to an unpredictable phase now," said Pyongyang's UN ambassador, according to Reuters. Washington is pushing a "hostile policy" against the North via the UN Security Council, the official said.