Pyongyang's state media reports that North Korean leader Kim Jong-un supervised the testing of the new weapon in a move that could heighten tensions over denuclearisation talks.
North Korean leader Kim Jong-un observed the successful test of "a newly-developed ultramodern tactical weapon," the nation's state media reported on Friday, though it didn't describe what sort of weapon it was.
It didn't appear to be a nuclear or missile-related test, a string of which last year had many fearing war before the North turned to engagement and diplomacy early this year. Still, any mention of weapons testing could influence the direction of currently stalled diplomacy between Washington and Pyongyang that's meant to rid the North of its nuclear weapons.
The North hasn't publicly tested any weapons since November of last year, but in recent days Pyongyang reportedly expressed anger at South Korea's resumption of small-scale military drills with the United States, and Friday's announcement could be in response to those drills.
Even if the test was a message for Washington and Seoul, Friday's report from the North was noticeably less belligerent than past announcements of weapons tests, and didn't focus on North Korean claims of US and South Korean hostility.
The North said the test took place at the Academy of National Defense Science and that Kim couldn't suppress his "passionate joy" at the success of the test. He was described as "so excited to say that another great work was done by the defense scientists and munitions industrial workers to increase the defense capability of the country."
The North said this new, unspecified weapon has been under development for a long time and will help strengthen the combat power of its army.
Last year's string of increasingly powerful weapons tests, many experts believe, put the North on the brink of a viable arsenal of nuclear-tipped missiles that can target anywhere in the mainland United States.
Diplomacy has stalled since a June summit between President Donald Trump and Kim in Singapore, with Washington pushing for more action on nuclear disarmament and the North insisting that the US first approve a peace declaration formally ending the Korean War. Trump and Kim are both interested in another summit, but it's unclear when it might happen.