SEOUL, South Korea -- North Korean leader Kim Jong Un observed the successful test of an unspecified "newly developed ultramodern tactical weapon," state media reported Friday, in an apparent bid to apply pressure on the United States and South Korea.

It didn't appear to be a test of a nuclear device or a long-range missile with the potential to target the U.S. A string of such tests last year had many fearing war before North Korea turned to engagement and diplomacy. Still, any mention of weapons testing could influence the direction of stalled diplomatic efforts spearheaded by Washington and aimed at ridding the North of its nuclear weapons.

The North hasn't publicly tested any weapons since November 2017, but in recent days Pyongyang reportedly expressed anger at U.S.-led international sanctions and ongoing small-scale military drills between South Korea and the United States.

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Earlier this month, North Korea's Foreign Ministry warned it could bring back its policy of bolstering its nuclear arsenal if it doesn't receive sanctions relief.

"It's North Korea-style coercive diplomacy. North Korea is saying 'If you don't listen to us, you will face political burdens,'" said analyst Shin Beomchul of Seoul's Asan Institute for Policy Studies.

Diplomacy has stalled since a summit between Kim and U.S. President Donald Trump in June, with Washington pushing for more action on nuclear disarmament and the North insisting that the U.S. first approve a peace declaration formally ending the Korean War and lift sanctions.

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.

Yang Wook, a Seoul-based military expert, said a "tactical weapon" in North Korea refers to "a weapon aimed at striking South Korea, including U.S. military bases" there, so the North may have tested a short-range missile or a multiple rocket launch system.

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 U.S. and South Korean hostility.

Yang said the latest North Korean test won't completely break down nuclear diplomacy, though more questions would be raised about how sincere the North is about its commitment to denuclearization.

Asked about the test, the U.S. State Department said that American and North Korean officials are talking about implementing the commitments that Trump and Kim made during their June meeting in Singapore. Eugene Lee, spokeswoman of South Korea's Unification Ministry, declined to comment on Kim's inspection of the weapons test.

U.S. 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," 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.

Pence stressed that U.N. sanctions had to remain enforced.

It's 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 Defense Science and that Kim couldn't suppress his "passionate joy" at its success. 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."

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.

Trump and Kim are both interested in another summit, but it's unclear when it might happen. Pence has said the next meeting would allow the two leaders to put what they discussed in their last summit on paper.