The test is of "great significance" to strategic deterrence, the country's leader, Kim Jong-un, has said

The North Korean military has successfully test-fired an upgraded version of a large-caliber multiple rocket launch system (MLRS), state-run news agency KCNA has announced.

The missiles, equipped with new technology, struck a target 358.5 km (223 miles) off North Korea's shore, the agency said in a statement on Wednesday.

The day before, South Korea's military said it detected multiple short-range ballistic missiles launched from north of Pyongyang toward the Sea of Japan.

North Korean leader Kim Jong-un, who oversaw the test with his daughter Ju-ae, said the MLRS has been "improved to maximize its strike capability, and the mobility, intelligence."

The key feature of the upgraded launcher is the "self-steered precisely guided flight system," which allowed the accuracy of the rockets to be "remarkably" improved, Kim added, as cited by KCNA.

The test was aimed solely at raising the level of North Korea's deterrence "against a nuclear war," which requires it to possess "the most reliable offensive capability," he said.

The firing of the MLRS comes ahead of the first North Korean ruling party congress in five years, which is expected to take place in early February. The gathering "will clarify the next-stage plans for further bolstering the country's nuclear deterrence," according to Kim.

It coincided with US Under Secretary of Defense for Policy Elbridge Colby's visit to South Korea, where he discussed Seoul's plans to build nuclear-powered submarines.

Pyongyang has accused the US, South Korea, and Japan of undermining regional security by conducting joint military exercises, calling them an attempt to create an "Asian version of NATO."

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Russia and North Korea signed the Comprehensive Strategic Partnership Treaty in 2024. Russian President Vladimir Putin, in his New Year's greeting to Kim, said the relationship between the countries will "contribute to establishing a just order of the multi-polar world."