New worries have emerged as North Korea made a big leap testing its most advanced missile capable of striking the continental United States, but analysts say it is far from being the "breakthrough" hailed by the regime as it has yet to demonstrate key technologies, including successful re-entry through the atmosphere.
South Korean officials yesterday appeared to downplay the launch of Hwasong-15, rubbishing Pyongyang's claim that it has completed its nuclear weapons programme.
The missile, fired after a 75-day lull, flew nearly 960km over 53 minutes and reached an altitude of 4,500km before landing in waters inside Japan's exclusive economic zone on Wednesday. The provocation drew global condemnation and prompted Washington to urge tougher sanctions on the regime.
South Korea's Unification Ministry, however, said yesterday that the government "does not view the North as crossing the red line", as the latest test did not demonstrate full ICBM (intercontinental ballistic missile) capability.
A ministry spokesman also said the North is not likely to engage in further provocation soon, barring a drastic change in circumstances. The regime has a history of testing fewer missiles in winter, as the cold weather puts a strain on its fuel supplies and troops are redirected to help with crop harvesting.
The South Korean Defence Ministry acknowledged yesterday that Pyongyang had conducted a successful missile test, and that the Hwasong-15 is capable of flying over 13,000km and reaching Washington on a normal trajectory. But more analysis is needed to determine if it is a reliable long-range missile equipped with re-entry and final-phase precision guidance technologies, it said.
Based on photographs released by North Korea, the Hwasong-15 is quite different from the two Hwasong-14 missiles tested in July.
Defence officials said the new missile, at 21m, is about 2m longer than the previous model. This means it can carry more fuel, enabling it to fly longer and farther.
The Hwasong-15 also has a wider diameter - around 2m, or 30cm wider than the Hwasong-14 - which would allow a bigger and heavier warhead to be mounted on it.
Analysts agree that the greatest significance of the Hwasong-15 test was the increase in flight distance, but North Korea is still one or two years away from having full nuclear capability to strike the US.
Dr Bong Young Shik from Yonsei University's Institute for North Korean Studies told The Straits Times that the regime "still has a lot of homework to do, and a lot of technological hurdles to overcome".
He said North Korea will have to conduct more tests to figure out how to make the nuclear warhead lighter and resistant to high heat when the ICBM re-enters the atmosphere, as well as how to extend the range of the missile, and other requirements of the engine.
"All these technological hurdles have to be overcome before the North Korean leadership is ready to engage in diplomatic negotiations with Washington," he added.
Dr Graham Ong-Webb, a research fellow at the S. Rajaratnam School of International Studies, agreed the Hwasong-15 test is "certainly a major leap but not a breakthrough", as North Korea's missile research and development programme is still incomplete without re-entry tests.
"We can expect Pyongyang to test such technology into 2018 and once they have demonstrated success, then we can say it has more or less arrived," he told The Straits Times.
It also remains to be seen if the Hwasong-15 can indeed carry a very large and heavy warhead as the regime claimed. But Dr Ong-Webb warned that even with a smaller warhead, a nuclear-tipped Hwasong-15 "would still exact significant destruction on whatever city target it was sent to strike".