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 U.S.-South Korea military exercises, and that its weapons displays could intensify in the coming months if progress in talks isn't made.

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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 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 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.