South Korea says North's recent test was of rocket engine

South Korea's defense minister says North Korea's unspecified test at a rocket liftoff site was of a rocket engine and Seoul is deeply concerned by the test and several recent launches

It was the first official outside assessment of what North Korea called “a very important test” at its Tongchang-ri rocket launch site. The North’s Academy of National Defense Science said Sunday the test will have “an important effect on changing the strategic position” of North Korea.

Jeong didn’t elaborate on what the engine test was for but urged North Korea to stop “acts that escalate military tensions."

Many experts say the reported test indicates North Korea is preparing to launch a satellite-carrying rocket in a disguised test of long-range missile technology amid faltering U.S.-led diplomacy on ending the North Korean nuclear crisis.

The diplomacy has been stalemated for months, with North Korea pressing the United States to make concessions by year's end. North Korea has hinted at abandoning diplomacy and resuming nuclear and intercontinental ballistic missile tests, if the U.S. fails to meet that deadline.

In past months, North Korea launched a slew of short-range missiles and other weapons off its east coast into the sea. South Korea and parts of Japan would be within the range of those weapons, which don't pose a direct threat to the mainland U.S.

Analysts say ballistic missiles and rockets used in satellite launches share similar bodies, engines and other technology. They say each of the North's past satellite launches was believed to have improved its missile technology.