North Korea says it has successfully tested a solid-fuel rocket engine, state media said Thursday.
The claim came from leader Kim Jong Un while visiting a ground-based test site for the engine, the South Korean news agency Yonhap reported, citing official North Korean news agency KCNA.
Kim said the success of the test would "strike great horror and terror into the hearts of the enemies."
"We will make continued achievements in defence science that would make our enemies shudder with fear," Kim said.
Moon Sang Gyun, spokesman for South Korea's Ministry of National Defence, said North Korea "appears to be in the [early] stages of developing" solid-fuel rockets.
"North Korea's switch to solid fuel means it could do [missile] launches frequently," he added.
South Korea is preparing countermeasures, the spokesman added.
The test comes amid increased tensions on the peninsula, since North Korea detonated a nuclear device in January and launched a long-range rocket in February.
The North's isolated communist regime has test-fired missiles several times this month during annual joint exercises by South Korean and US forces, which Pyongyang describes as a rehearsal for invasion.
The US and South Korea say their military drills are defensive in nature.