North Korean leader Kim Jong-un oversaw the ground test of an upgraded rocket engine, state media reported Sunday, marking another key step in its weapons programme.
Defence experts believe North Korea is planning to use its solid-fuel rocket engines for launching intercontinental ballistic missiles.
The engines enable faster missile launches as they require little preparation before ignition.
The latest test was "part of the national defence development plan in the period of the new five-year plan", Pyongyang's official Korean Central News Agency (KCNA) said, without elaborating on the date or location of the test.
It was the first officially confirmed high-thrust solid-fuel engine test since September last year, when state media said an engine generated a maximum thrust of 1,971 kilonewtons.
KCNA reported the recent test had achieved a higher thrust of 2,500 kilonewtons.
The development demonstrates North Korea's "resolve to acquire missiles capable of hitting targets around the globe", Hong Min, an analyst at the Korea Institute for National Unification, told AFP.
"Given the increased maximum thrust, this indicates its intention to possess ICBMs with global strike range, as well as the ability to overwhelm missile defence systems," he added.
Photos released by KCNA showed leader Kim Jong-un inspecting what appeared to be part of the engine, flanked by officials.
Another image showed flames erupting from a ground-mounted engine, illuminating the surrounding test site in orange light.
Kim said that North Korea's defence capabilities had entered "a significant phase of change" in building up its strategic forces.
The North has already demonstrated it has mastered the engine technology needed to launch a missile capable of reaching the US mainland with a lower-thrust engine, said Lee Ho-ryung of the Korea Institute for Defense Analyses.
"They have already passed that mark," she said.
The question is no longer whether a missile could reach the US, but whether it could carry multiple warheads, she said.
A multi-warhead missile can strike multiple targets with a single launch while overwhelming defence systems through simultaneous, dispersed reentry vehicles.
"A multi-warhead missile needs higher thrust power because of its heavier weight," she said.
"In order for the North to show it can launch a multi-warhead ICBM, it needs a test launch to prove its mastery of such technology."
Pyongyang last test-fired an ICBM in October 2024.
Kim also visited a special forces training base, according to a separate KCNA report, inspecting drills in which photos showed soldiers wielding weapons, including an axe and a sledgehammer.
The demonstration "showed the physical and technical ability they have prepared to be a match for a hundred combatants with iron fists", KCNA said.
