North Korea Says Kim Oversaw Test of Upgraded Solid-Fuel Missile Engine

North Korean leader Kim Jong Un oversaw a ground test of an upgraded solid-fuel rocket engine made with a composite carbon fiber material, North Korea’s state Korean Central News Agency (KCNA) reported Sunday, according to Yonhap News Agency and CBS News. The Associated Press, whose reporting CBS News carried, described the engine as meant for weapons capable of reaching the U.S. mainland; that description comes from the AP and was not independently confirmed.

KCNA said the engine has a maximum thrust of 2,500 kilonewtons. Yonhap put the thrust of the September test at 1,971 kilonewtons, which CBS News rounded to about 1,970. KCNA did not say when or where the test took place, both outlets reported, and independent reporters did not cover it. CBS News said a government photograph shows a large jet of flame. Yonhap reported that the engine is assessed to have been developed for the Hwasong-20 intercontinental ballistic missile, which is under development.

KCNA said the test was part of a five-year national defense plan to upgrade what it calls “strategic strike means,” which the AP explained is a term for nuclear-capable ballistic missiles and other weapons. Kim said the test had “great significance” in putting the country’s strategic military capabilities at the highest level, according to Yonhap and CBS News. KCNA also said Kim called for further steps to develop the state’s strategic forces in quality and quantity, Yonhap reported.

Solid-fuel missiles are easier to move and conceal than liquid-fuel weapons, which generally must be fueled before liftoff, the AP explained in the CBS News report. Some observers believe a push for more engine power is tied to efforts to place several warheads on one missile to improve the chance of defeating U.S. defenses, the AP reported.

Some experts are skeptical, the AP reported. Lee Choon Geun, an honorary research fellow at South Korea’s Science and Technology Policy Institute, said the report could be “bluffing” because it left out key information such as the engine’s total combustion time. He said the engine program may be facing delays, or the country may have decided to develop a better engine, possibly with Russian assistance. These points come from the AP account and were not independently confirmed.

North Korea described the September test as the ninth and final ground test of a solid-fuel engine intended for intercontinental ballistic missiles, the AP noted in the CBS News report, and observers at the time expected an ICBM test launch with that engine. According to the same account, that launch had not happened as of Sunday.

Yonhap added that KCNA reported Kim also inspected a separate test of a new main battle tank’s protection system, which KCNA said succeeded, and visited a special operations training base. These are KCNA’s claims; neither outlet independently verified them.