Library image of Kim Jong Un, who state media say could not suppress his "passionate joy" at the success of the latest missile test (Picture: PA).
North Korean state media says the country's leader, Kim Jong Un, has supervised the successful testing of a "newly developed ultramodern tactical weapon."
It is believed to be part of an apparent bid to apply pressure on the United States and South Korea.
The announcement gave no details of the type of weapon, saying only that it had been developed over a long period.
It did not appear to be a test of a nuclear device or a long-range missile with the potential to target the US.
A string of such tests last year had many fearing war before the North turned to engagement and diplomacy.
This week a US think-tank said it had identified at least 13 ballistic missile sites in North Korea that have not been declared by Pyongyang.
The North has not publicly tested any weapons since November 2017, but in recent days Pyongyang reportedly expressed anger at US-led international sanctions and ongoing small-scale military drills between South Korea and the United States.
Earlier this month, North Korea's Foreign Ministry warned it could bring back its policy of bolstering its nuclear arsenal if it does not receive sanctions relief.
Shin Beomchul, an analyst of Seoul's Asan Institute for Policy Studies, said:
"It's North Korea-style coercive diplomacy. North Korea is saying 'If you don't listen to us, you will face political burdens'."
Diplomacy has stalled since a summit between Mr Kim and US president Donald Trump in June, 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 and lift sanctions.
Mr Shin said the weapon North Korea tested could be a missile, artillery, an anti-air gun, a drone or other high-tech conventional weapons systems.
Asked about the test, the US State Department said that American and North Korean officials are talking about implementing the commitments that Mr Trump and Mr Kim made during their June meeting in Singapore.
Eugene Lee, the spokeswoman of South Korea's Unification Ministry, declined to comment on Mr Kim's inspection of the weapons test.
US vice president Mike Pence, attending a Southeast Asian summit in Singapore, cited the "great progress" made on North Korea but said more had to be done.
A year and a half ago, "nuclear tests were taking place, missiles were flying over Japan and there were threats and propagations against our nation and nations in the region," Mr Pence said.
"Today, no more missiles are flying, no more nuclear tests, our hostages have come home, and North Korea has begun anew to return fallen American heroes from the Korean War to our soil. We made great progress but there's more work to be done," he said.
Mr Pence stressed that UN sanctions had to remain enforced.
It is the first publicly known field inspection of a weapons test by Kim Jong Un since he observed the testing of the Hwasong-15 intercontinental ballistic missile in November of last year, according to South Korea's Unification Ministry.
The North said the test took place at the Academy of National Defence Science and that Mr Kim could not suppress his "passionate joy" at its success.
Mr Trump and Mr Kim are both interested in another summit, but it is unclear when it might happen.
Mr Pence has said the next meeting would allow the two leaders to put what they discussed in their last summit on paper.