North Korea has achieved "meaningful" progress in upgrading technologies for a rocket engine which was tested last weekend in an exercise observed by leader Kim Jong-un, the South's defense ministry said Monday.
The weekend test at the Sohae satellite launching ground was successful, according to Pyongyang's official KCNA news agency. Kim was quoted as saying the world would soon see "what eventful significance the great victory won today carries".
The test was conducted to confirm the overall technical indices of the engine, such as features of its thrust power in the combustion chamber, accurate movement of the turbine pump, control system and various valves, and their structural safety and reliability, KCNA said.
"It's assessed that through this test, meaningful progress appeared to have been made in engine efficiency," South Korean defense ministry spokesman Moon Sang-gyun told reporters. North Korea tested one main engine with four backup boosters, he said, calling for a further study to get precise information.
In its previous test in September last year, Pyongyang checked an 80-ton force rocket that burned for 200 seconds.
In February, North Korea claimed to have successfully launched a new strategic intermediate-range ballistic missile with an improved solid fuel engine capable of carrying a nuclear warhead more accurately from any place. At that time Pyongyang said it has acquired improved technologies related to a nuclear warhead, re-entry and guided flight.
Kim has vowed to launch more rockets capable of carrying nuclear warheads, claiming Pyongyang has acquired re-entry technology, despite doubts about its ability to miniaturize a nuclear warhead to be mounted on an intercontinental ballistic missile.
In its 2016 defense white paper, the South's defense ministry said Pyongyang has significant advancements in its ability to miniaturize nuclear warheads and enrich uranium. Last year, North Korea tested eight intermediate-range Musudans with an estimated range of more than 3,000 kilometers that could reach as far as Guam.
This year, North Korea has threatened to launch an ICBM at a time and place determined by Kim who said in his New Year's address that Pyongyang had reached the final stage of ICBM development. US President Donald Trump vowed to stop Pyongyang from mastering ICBM capabilities.
Pyongyang could launch a road-mobile KN-08 ICBM and its advanced version after adding a yet-unseen reentry vehicle, John Schilling, a US missile expert, said in an article published by 38 North, the website of a US research institute.
Lim Chang-won = email@example.com