North Korea leader Kim Jong Un reportedly supervised another test-firing of a new multiple rocket launcher system, which could potentially enhance the country's ability to strike targets in South Korea and US military bases there.

Experts say the North's increased testing activity is aimed at ramping up pressure on Washington and Seoul over stalled nuclear negotiations with the United States and planned U.S.-South Korea military exercises.

North Korea has said Kim supervised the first test of the same rocket artillery system on Wednesday.

On July 25, North Korea fired two short-range ballistic missiles that Seoul officials said flew 600 kilometers (370 miles) before landing in the sea.

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SEOUL, South Korea (AP) — North Korea said Saturday its leader Kim Jong Un supervised another test-firing of a new multiple rocket launcher system that could potentially enhance the country's ability to strike targets in South Korea and U.S. military bases there.

The report by Pyongyang's official Korean Central News Agency came a day after South Korea's military said it detected North Korea firing projectiles twice into the sea off its eastern coast in its third round of weapons tests in just over a week.

Experts say the North's increased testing activity is aimed at ramping up pressure on Washington and Seoul over stalled nuclear negotiations with the United States and planned US-South Korea military exercises, and that its weapons displays could intensify in the coming months if progress in talks isn't made.

North Korea has said Kim supervised the first test of the same rocket artillery system on Wednesday. KCNA said Kim expressed "great satisfaction" over Friday's tests, which it said confirmed the system's "altitude control level flight performance, track changing capability, accuracy of hitting a target and warhead explosion power of the guided ordnance rocket."

The report didn't include any direct mention of the United States or South Korea.

South Korea's presidential office had said the U.S. and South Korean militaries shared an assessment that Friday's launches were likely of short-range ballistic missiles.

South Korea's military had also concluded the weapons North Korea tested on Wednesday are ballistic missiles and maintained its assessment even after the North described them as a newly developed "large-caliber multiple launch guided rocket system."

South Korea's Joint Chiefs of Staff said Friday's launches were conducted at 2:59 a.m. and 3:23 a.m. from an eastern coastal area and the projectiles flew 220 kilometers (137 miles). The range would be enough to cover the metropolitan area surrounding Seoul, where about half of South Koreans live, and a major U.S. military base just outside the city.

On July 25, North Korea fired two short-range ballistic missiles that Seoul officials said flew 600 kilometers (370 miles) before landing in the sea.

North Korea said those tests were designed to deliver a "solemn warning" to South Korea over its purchase of high-tech, U.S.-made fighter jets and the planned military drills, which Pyongyang calls an invasion rehearsal. The North also tested short-range missiles on May 4 and 9.

Read more: North Korea's new weapons have South Korea's F-35s in their sights

The North's new launches came as the United Kingdom, France and Germany — following a closed U.N. Security Council briefing — condemned the North's recent ballistic activity as violations of U.N. sanctions and urged Pyongyang to engage in "meaningful negotiations" with the United States on eliminating its nukes. The three countries said international sanctions should remain in place until North Korea's nuclear and ballistic missile programs are dismantled.

In a separate report carried through KCNA on Saturday, an unidentified spokesperson of North Korea's Foreign Ministry criticized the statement released by the three countries, saying that the North never has and never will recognize the U.N. resolutions it sees as a "grave provocation" against its government.

The spokesperson said North Korea has never signed an agreement with any country to limit the range of missiles and other projectiles it tests and wasn't bound to any legal requirement. The spokesperson said the North's unilateral suspension of nuclear and intercontinental range ballistic missile tests, announced by Kim last year amid a diplomatic outreach to Washington, was based on "goodwill and consideration for a dialogue power."

The spokesperson also seemed to reaffirm the North's stance that the weapons it tested on Wednesday were rocket artillery, not ballistic missiles.

"It is the very self-evident truth that any projectile draws a ballistic curve, not a straight line owing to earth gravity. The UNSC takes issue with the firing based on the ballistic technology, not the range of the projectile, which means that the DPRK should give up the right to self-defense," the spokesperson said, referring to North Korea by its formal name, the Democratic People's Republic of Korea.

President Donald Trump said on Thursday he wasn't worried about the weapons recently tested by North Korea, calling them "short-range missiles" that were "very standard."

However, the North's recent weapons demonstrations have dampened the optimism that followed Trump's impromptu summit with Kim on June 30 at the inter-Korean border. The leaders agreed to resume working-level nuclear talks that stalled since February, but there have been no known meetings between the two sides since then.

The North has claimed the United States would violate an agreement between the leaders if it moves on with its planned military exercises with South Korea. It said it will wait to see if the August exercises actually take place to decide on the fate of its diplomacy with Washington and also whether to continue its suspension of nuclear and ICBM tests.