SEOUL, South Korea — North Korea’s latest test of a rocket engine showed that the country was making “meaningful progress” in trying to build more powerful rockets and missiles, South Korean officials said on Monday.

North Korea said on Sunday that it had conducted a ground jet test of a newly developed high-thrust missile engine, which its leader, Kim Jong-un, called “a great event of historic significance.” Using the characteristic bombast of such announcements, he said that the test heralded “a new birth” of the country’s rocket industry and that “the whole world will soon witness what eventful significance the great victory won today carries.”

The North’s rival, South Korea, acknowledged on Monday that the test represented a breakthrough. Lee Jin-woo, a spokesman at the Defense Ministry, said it showed that the North was developing a more sophisticated rocket engine. The model that the North tested included a cluster consisting of a main engine and four vernier thrusters — smaller engines used to adjust the craft’s velocity and stability.

“Through this test, it is found that engine function has made meaningful progress,” Mr. Lee said during a news briefing, without divulging further details.