N Korea conducts engine test for missile capable of targeting US mainland

SEOUL, Mar 29 (AP): North Korean leader Kim Jong Un observed a test of an upgraded solid-fuel engine for weapons capable of reaching the U.S. mainland, and called it a significant development boosting his country's strategic military arsenal, state media reported Sunday.
While the test was in line with Kim's stated goal of acquiring more agile, hard-to-detect missiles targeting the U.S. and its allies, some experts speculate North Korea's claim may be an exaggeration. Missiles with built-in solid propellants are easier to move and conceal their launches than liquid-fuel weapons, which in general must be fueled before liftoffs and cannot last long.
The official Korean Central News Agency reported Kim watched the ground jet test of the engine using a composite carbon fiber material. It said the engine's maximum thrust is 2,500 kilonewtons, up from about 1,970 kilonewtons reported in a similar solid-fuel engine test in September.
KCNA reported the test was conducted as part of the country's five-year arms build-up meant to upgrade "strategic strike means," a term referring to nuclear-capable ballistic missiles and other weapons. Kim said the latest engine test had "great significance in putting the country's strategic military muscle on the highest level," according to KCNA. The agency did not say when or where the test occurred.
North Korea's report on the latest test could be "bluffing" as it didn't disclose some key information like the engine's total combustion time, said Lee Choon Geun, an honorary research fellow at South Korea's Science and Technology Policy Institute.
When North Korea reported about the previous engine test in September, it described it as the ninth and final ground test of a solid-fuel engine that it earlier said would be used for intercontinental ballistic missiles. Observers predicted at the time North Korea would soon test-launch an ICBM loaded with that engine, but it hasn't done so yet.
North Korea's solid-fuel engine program may be facing some delays or the country might have determined to develop a better engine, possibly with Russian assistance, Lee said. Cooperation between the countries has deepened in recent years, with the North sending troops and conventional weapons to support Russia's war against Ukraine.