North Korea successfully tested a solid-fuel engine for its new-type intermediate-range hypersonic missile, state media reported Wednesday, claiming a progress in efforts to develop a more powerful, agile missile designed to strike faraway US targets in the region.

A hypersonic missile is among an array of high-tech weapons systems that North Korean leader Kim Jong Un publicly vowed to introduce in 2021 to cope with what he called deepening US hostility. Outside experts say Kim wants a modernized weapons arsenal to wrest US concessions like sanctions relief when diplomacy resumes.