North Korea has carried out a test of an upgraded solid-fuel engine for missiles it claims can strike the U.S. mainland. Observed by Kim Jong Un, the test underscores the country’s persistent pursuit of enhanced nuclear and missile capabilities, even as experts caution that the claim’s details remain incomplete.

North Korea has conducted a new military test, launching two unidentified projectiles into the waters between South Korea and Japan. This marks the second such test this month, raising concerns over regional security and North Korea’s military intentions.