Story highlights Schoolchildren in northern Japan prepare for a North Korean missile attack

Analyst: North Korea's improved technology could lead to more accurate ICBMs

Seoul, South Korea (CNN) North Korea is touting a "great leap forward" in its rocket program after the successful testing of a new high-thrust engine, state media reported Sunday.

North Korea says it successfully tested a high-thrust rocket engine.

The test measured the thrust power in the combustion chamber, the structural safety and reliability of the engine, and the movement of the turbine pump, the Korean Central News Agency said. It reportedly took place at the Sohae Satellite Launching Ground, in North Pyongan Province.

Leader Kim Jong Un is congratulated after the rocket engine test.

CNN military analyst Lt. Gen. Mark Hertling said advances in North Korea's rocket system could help with the country's development of ICBMs -- intercontinental ballistic missiles.

"Some of these technologies which the North Koreans are including in their rocket expansion program actually have to do with a covert method of firing missiles without being detected in advance of actually exploding the devices. So that's part of the issue," Hertling said.

"The other piece is when you're talking about an intercontinental ballistic missile, the types of warheads and the amount of weight that are in the missile itself have to be launched off of a pad. And the better they can improve their technology to do that, the more accurate these systems are going to be -- not only from leaving the pad, but also going into the atmosphere and then hitting the target on the other side."

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