SEOUL • North Korea has likely mastered the technology to power the different stages of an intercontinental ballistic missile (ICBM) and may show it off soon, analysts said yesterday, but it is likely still a long way from being able to hit the mainland United States.
North Korean state media announced its latest rocket-engine test on Sunday, saying that it would help the country achieve world-class satellite-launch capability, indicating a new type of engine for an ICBM.
The test showed "meaningful" progress, a spokesman for South Korea's Defence Ministry said, with the firing of a main engine and four auxiliary engines as part of the development of a new rocket booster.
The announcement of the test came as US Secretary of State Rex Tillerson was in China at the end of his first visit to Asia for talks dominated by concern about the North's nuclear and missile programmes.
Meanwhile, top US nuclear envoy Joseph Yun arrived in Seoul last night for talks with South Korean officials on how to deal with the growing nuclear and missile threats from Pyongyang.
Mr Yun is expected to share the results of Mr Tillerson's discussions in Beijing with Seoul and exchange views on how to coordinate policies against Pyongyang.
North Korea has held five nuclear tests and a series of missile launches in defiance of United Nations resolutions, and is believed by experts and officials to be working to develop nuclear-warhead missiles that could reach the US.
The rocket engine that North Korea tested over the weekend appeared to be powered with liquid fuel, said Dr Melissa Hanham of the James Martin Centre for Nonproliferation Studies, rather than the solid fuel that the regime's engineers have been working on recently.
Liquid fuel rockets are easier to spot with satellites because they require more outdoor preparation.
"There is nothing about this rocket engine itself that makes me more terrified, but taken as a whole, it's pretty clear that they are trying to give us proof of their growing missile programme," she said.
A South Korean expert on rocket engineering said the engine test was ominous.
"This was a comprehensive test for the first-stage rocket for an ICBM, and that is why it was dangerous," Mr Kim Dong Yub of the Institute for Far Eastern Studies in Seoul told Reuters. "It appears North Korea has worked out much of its development of the first-stage rocket booster."
But he added that the North had still not mastered the atmospheric re-entry technology needed for an ICBM, so it had work to do before being able to hit the US.
Nevertheless, he said, it might soon demonstrate that it has perfected the system's booster rocket stage.
"What could be next is they would make a new type of ICBM with this new engine system and launch it - not the entire stages, but to make only the first stage, fly about 400km and drop.
"They are not going to show it all at once," Mr Kim said.
US aerospace expert John Schilling said the engine appeared too big for any ICBM that North Korea was working on but would be a good fit for the second stage of a new space rocket it is planning to build.
And Mr Joshua Pollack of the Washington-based Nonproliferation Review said the design - with four verniers or steering nozzles - was familiar in the North's older, long-range rockets launched to deliver objects previously, but added that it could be the second stage of a missile, not the first.
"Since the comparable display of 2016 was the first stage of an ICBM, we could speculate that this is the second stage," Mr Pollack told Reuters in an e-mail.
China yesterday said the situation with North Korea was at a new crossroads with two scenarios - a deterioration to war or a diplomatic solution. "Any chance for dialogue must be seized, as long as there's hope," Foreign Minister Wang Yi said.
REUTERS, WASHINGTON POST