Seoul, South Korea (CNN) North Korea is believed to be moving an intercontinental ballistic missile (ICBM), a South Korean lawmaker said after being briefed by the country's intelligence service. 
 
 The lawmaker told CNN Tuesday it was unclear when the movement was detected, what the direction of the projectile was and how it was being transported. He attended the briefing by South Korea's National Intelligence Service (NIS) in Seoul on Monday. 
 
 All eyes have been on North Korea following the country's sixth test of a nuclear weapon Sunday. Seismological data indicated the weapon was the most powerful ever detonated by the rogue nation, nuclear experts said. 
 
 North Korean state media claimed it detonated a hydrogen bomb, also known as a thermonuclear weapon, which could be fitted atop a long-range missile capable of striking the United States. 
 
 Weapons experts say it's almost impossible to verify if the warhead and missile could be successfully paired unless North Korea were to actually fire a nuclear-tipped ICBM. 
 
 The country has test-fired a number of missiles this summer, including two long-range ones in July and an intermediate-range one in August that overflew the Japanese island of Hokkaido. 
 
 Lawmaker Kim Byung-kee told reporters Monday after the same briefing that the NIS said North Korea may test-fire an ICBM towards the North Pacific at a lower angle than the two tests in July, which were lofted, meaning they flew higher but not as far. 
 
 Live-fire drills 
 
 The South Korean Navy announced Tuesday it conducted live-fire drills off the east coast of the Korean Peninsula to check its "immediate operational readiness" after the country's Air Force and Army conducted their own joint drills. 
 
 South Korea's Navy conducted a live-fire drill in the waters off the east coast of the Korean Peninsula in response to North Korea's Sunday nuclear test. 
 
 "Wherever it is, whether on or under water, if North Korea provokes, we will immediately destroy and bury them at sea," the Navy said in a statement. 
 
 While South Korean forces have flexed their muscles, diplomats in New York gathered at the United Nations and condemned the nuclear test. 
 
 Nikki Haley, the American ambassador to the United Nations, said Monday the United States would circulate a resolution in response after urging her colleagues to adopt the strongest sanctions measures possible to stop Pyongyang's nuclear program. 
 
 "Enough is enough," Haley said. "North Korea has basically slapped everyone in the face in the international community that has asked them to stop." 
 
 Another lawmaker who attended the Monday briefing, Lee Cheol-woo, told reporters the NIS informed them that Pyongyang had dug extra tunnels at the nuclear test site and could explode another one "anytime." 
 
 Rift? 
 
 South Korean President Moon Jae-in and his American counterpart, President Donald Trump, spoke by phone Monday and agreed to lift current restrictions on the payload weight of South Korea's ballistic missiles, according to a South Korean presidential spokesman. 
 
 But signs of a rift between the two leaders have become apparent despite the decades-long alliance between Seoul and Washington. 
 
 Their phone call came a day after the nuclear test and followed a tweet from Trump in which he criticized South Korea for "appeasement" when it comes to dealing with its northern neighbor. 
 
 Moon has long been a proponent of more dialogue and diplomacy with North Korea, whereas Trump has said recently that "talking is not the answer." 
 
 "This is not the time for these two countries to be showing these cracks. North Korea is going to exploit that," said Jean Lee, a North Korea expert and global fellow at the Wilson Center. 
 
 Trump spoke twice with Japanese Prime Minister Shinzo Abe over the weekend, once before the nuclear test and once after. 
 
 Diplomacy 
 
 Moon and Abe are both traveling to the eastern Russian city of Vladivostok for an economic summit taking place Wednesday and Thursday. 
 
 They will be joined by Russian President Vladimir Putin, who is currently in China for a summit of the BRICS nations -- Brazil, Russia, India, China and South Africa. He reiterated calls for North Korea to stop nuclear tests but said dialogue needs to be the answer. 
 
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 "Russia condemns these exercises from North Korea. We think these exercises are provoking in nature but we should not forget and North Koreans should not forget what happened in Iraq," he said. 
 
 "Sanctions of any kind are usefulness and ineffective ... they will eat grass but they will not turn away from the path that will provide for their security," Putin said, referring to accusations that Pyongyang spends too much on weapons programs while its citizens starve. ||||| If claim of ICBM launch is confirmed, it could move regime closer to being able to strike US mainland 
 
 North Korea claims to have conducted its first test of an intercontinental ballistic missile (ICBM) , a development that, if confirmed, could move the regime closer to being able to strike the US mainland and dramatically strengthen its hand in negotiations with Washington. 
 
 South Korean and Japanese officials said they were studying the data to confirm whether or not it was an ICBM, but analysts said it appeared the missile had the range to strike Alaska but not other parts of the continental US. 
 
 Later there were reports in the US that officials believe North Korea may have fired its first intercontinental missile, though there was no official public statement from the US about this. 
 
 Why does the North Korean regime pursue a nuclear programme? Much of the regime’s domestic legitimacy rests on portraying the country as under constant threat from the US and its regional allies, South Korea and Japan. 
 
 To support the claim that it is in Washington’s crosshairs, North Korea cites the tens of thousands of US troops lined up along the southern side of the demilitarised zone – the heavily fortified border dividing the Korean peninsula. Faced with what it says are US provocations, North Korea says it has as much right as any other state to develop a nuclear deterrent. North Korea’s leader Kim Jong-un is also aware of the fate of other dictators who lack nuclear weapons. 
 
 
 
 
 
 The launch, which came as Americans prepared to mark Independence Day, triggered a Twitter outburst from President Donald Trump who urged China to act to “end this nonsense once and for all”. 
 
 In a joint statement released after the missile test, Russia and China condemned the launch and proposed that North Korea declare a moratorium on nuclear and missile tests, while at the same time calling on Washington to immediately halt deployment of its THAAD anti-missile system in South Korea. 
 
 In a rare announcement on state North Korean television, an emotional newsreader said Kim Jong-un had personally overseen the “landmark” test of a Hwasong-14 missile. 
 
 North Korea was now a “a strong nuclear power state” and had “a very powerful ICBM that can strike any place in the world,” the newsreader said. 
 
 She added that the missile had reached an altitude of 2,802km (1,741 miles) and flew 933km (580 miles) – longer and higher than any of the regime’s previous similar tests. Those figures roughly concurred with analysis by Japanese and South Korean officials. 
 
 Early indications were that the missile was a single-stage device. 
 
 
 
 But later, NBC News cited two unnamed US officials saying they now believed it was “two stage”, and CNN quoted one official saying it was a “probable” ICBM and that the ongoing assessment suggested a second-stage booster did ignite and produced additional flight for 30 seconds. 
 
 
 
 While the apparent advancement in North Korea’s missile technology will add to concerns that the regime is moving closer to developing the capacity to strike the US mainland, many analysts still doubt whether it can miniaturise a nuclear weapon sufficiently to fit it on to a missile. They also believe the regime is unlikely to have mastered the technology needed for an ICBM to survive re-entry into Earth’s atmosphere. 
 
 South Korea’s military confirmed that North Korea had fired an “unidentified ballistic missile” into the Sea of Japan – known in North Korea as the East Sea of Korea – from Banghyon in North Pyongan, a province near its border with China. 
 
 The timing of North Korea’s 11th launch this year – on the eve of the US Independence Day holiday and just before the start of the G20 summit in Hamburg – was significant. It came soon after Donald Trump met the South Korean president, Moon Jae-in, in Washington, and held telephone discussions dominated by Pyongyang’s missile and nuclear weapons programmes with the Chinese president, Xi Jinping, and Japan’s prime minister, Shinzo Abe. 
 
 The missile landed in Japan’s exclusive economic zone, the South Korean military and Japanese government said. 
 
 Facebook Twitter Pinterest A screengrab from footage on North Korean TV purporting to show preparations for Tuesday’s missile test. Photograph: Korean state television 
 
 Tokyo strongly protested against what it called a clear violation of UN resolutions banning Pyongyang from developing ballistic missile technology. 
 
 North Korea's missile test: everything you need to know Read more 
 
 The US Pacific Command said it detected and tracked the “single launch of a land-based, intermediate-range ballistic missile” for 37 minutes near an airfield in Panghyon, about 60 miles north-west of Pyongyang - a flight time longer than any similar previous tests. 
 
 The joint statement from Russia and China, issued shortly after President Vladimir Putin and Chinese President Xi Jinping held wide-ranging talks in the Kremlin, called on North Korea, South Korea and the United States to sign up to a Chinese de-escalation plan designed to defuse tensions around Pyongyang’s missile programme. 
 
 The plan would see North Korea suspend its ballistic missile programme and the United States and South Korea simultaneously call a moratorium on large-scale missile exercises, both moves aimed at paving the way for multilateral talks. 
 
 “The situation in the region affects the national interests of both countries,” the joint statement said. “Russia and China will work in close coordination to advance a solution to the complex problem of the Korean Peninsula in every possible way.” 
 
 The joint declaration also called on Washington to immediately halt deployment of its THAAD anti-missile system in South Korea, a move Washington says is necessitated by the North Korean missile threat. The statement said Washington was using North Korea as a pretext to expand its military infrastructure in Asia and risked upsetting the strategic balance of power in the area. 
 
 On Monday China’s ambassador to the United Nations had warned of “disastrous” consequences if world powers fail to find a way to ease tensions with North Korea that risked getting “out of control”. 
 
 North Korea has increased the frequency of tests this year as it attempts to develop a missile capable of carrying a miniaturised nuclear warhead as far as the US mainland – a geopolitical game-changer that Trump has vowed “won’t happen”. 
 
 The regime’s most recent missile test before Tuesday came on 8 June when it launched a new type of cruise missile that Pyongyang said was capable of striking US and South Korean warships “at will”. 
 
 Facebook Twitter Pinterest Kim Jong-un studies the launch site for Tuesday’s missile test. Photograph: Korean state television 
 
 David Wright, co-director of the Global Security Program at the US-based Union of Concerned Scientists, said in a blogpost the initial assessments of the flight time and distance suggested the missile fired on Tuesday could have a maximum range of roughly 6,700km (4,160 miles). “That range would not be enough to reach the lower 48 states or the large islands of Hawaii, but would allow it to reach all of Alaska,” he said. 
 
 Shea Cotton, a researcher at the James Martin Center for Nonproliferation Studies in the US, suggested the launch was deliberately timed to coincide with the anniversary of the US declaration of independence. “It’s already 4th of July in North Korea,” he said on Twitter. “I somewhat suspect they’re shooting off some fireworks today specifically because of that.” 
 
 South Korea’s joint chiefs of staff immediately briefed Moon. Since taking office on 10 May, Moon has tried to push cautious engagement with Pyongyang, but the regime has continued its missile tests, insisting it has the right to develop a nuclear deterrent to counter what it calls growing military provocations by the US. 
 
 Trump and Moon agreed to apply “maximum pressure” to persuade North Korea to abandon its nuclear and ballistic missile programmes, but agreed they were open to dialogue with the regime “under the right circumstances”. 
 
 Trump declared the US had run out of patience with North Korea over its weapons programme. “Together, we are facing the threat of the reckless and brutal regime in North Korea,” he said. “The nuclear and ballistic missile programs of that regime require a determined response.”
– Following North Korea's most powerful weapons test yet on Sunday, a South Korean lawmaker tells CNN his country's intelligence service believes the North has an intercontinental ballistic missile (ICBM) on the move. Things get pretty vague beyond that: He didn't know the method of transport or when the movement was noticed. But Reuters does pick up some alleged details on those fronts, via an unnamed source quoted by South Korea’s Asia Business Daily. Its source says the ICBM started moving Monday, is only being moved at night, and is headed toward the nation's west coast. Reuters notes there's some likelihood that another test could come on or around Saturday: Sept. 9 is the country's founding day holiday. CNBC notes North Korea conducted a nuke test on Sept. 9, 2016. Two more details that allegedly came from the South's National Intelligence Service briefing: word that additional tunnels have been dug out at the North's nuclear test site that would facilitate future detonations, and suspicions that the next ICBM test firing might be directed toward the North Pacific but aimed at a lower angle, which would in theory allow it to fly further than previous tests, which had more of an upward trajectory. Meanwhile, the White House tells Reuters it has given "in-principle approval" to a request by South Korean President Moon Jae-in to abolish a limit regarding warhead weights, a move that would strengthen the power with which it could attack the North, if necessary. Meanwhile, Vladimir Putin on Tuesday gave his take on the situation: North Korea "will eat grass but will not give up the (nuclear) program if they don't feel safe."