SEOUL, South Korea (AP) — North Korea said Wednesday leader Kim Jong Un supervised a live-fire demonstration of newly developed, short-range ballistic missiles intended to send a warning to the United States and South Korea over their joint military exercises.

The official Korean Central News Agency said two missiles launched from a western airfield flew across the country and over the area surrounding the capital, Pyongyang, before accurately hitting an island target off its eastern coast.

Its four rounds of weapons demonstrations in two weeks come during a stalemate in nuclear negotiations and after President Donald Trump repeatedly dismissed the significance of the tests, even though the weapons show North Korea’s ability to strike at U.S. allies South Korea and Japan and its military bases there.

Experts say Trump’s downplaying of the North’s weapons displays allowed the country more room to advance its capabilities and build leverage ahead of negotiations, which could possibly resume sometime after the end of the allies’ drills later this month.

Lee Sang-min, spokesman from South Korea’s Unification Ministry, said North Korea’s recent testing activity doesn’t help efforts to stabilize peace and called for Pyongyang to uphold an inter-Korean agreement reached last year to form a joint military committee to discuss reducing military tensions. He did not provide a specific answer when asked whether Seoul believes the North’s weapons display will intensify.

The KCNA said the launches early Tuesday verified the reliability and combat ability of “new-type tactical guided missiles.” Kim expressed satisfaction and said the launches would send an appropriate level of warning to the military exercises between the United States and South Korea that began on Monday, the report said.

Pyongyang’s official Rodong Sinmun also published photos showing what appeared to be a missile soaring from a launcher installed on a vehicle and Kim smiling and celebrating with military officials.

KCNA’s report came a day after South Korea’s military said it detected two early morning launches that were likely ballistic missiles.

Seoul’s Joint Chiefs of Staff said the projectiles traveled about 450 kilometers (279 miles) on an apogee of 37 kilometers (23 miles) before landing in waters off the country’s eastern coast. It said the projectiles showed similar flight characteristics to short-range missiles North Korea fired on July 25.

South Korea’s military had described those missiles as similar to the Russian-made Iskander, a solid-fuel, nuclear-capable missile that is highly maneuverable and travels on low trajectories, improving its chances of evading missile defense systems. Last week, North Korea conducted two test firings of what it described as a new rocket artillery system.

Kim Dong-yub, an analyst at Seoul’s Institute for Far Eastern Studies, said North Korea’s decision to fly the missiles over its capital indicated it was confident about the reliability of the system. Kim, a former South Korean military official who had participated in inter-Korean military talks, said Kim Jong Un is making a measured effort to advance the North’s military capabilities without allowing nuclear negotiations with Washington collapse.

North Korea has denounced Washington and Seoul over their joint military exercises. South Korea confirmed they started Monday but hasn’t given details about the drills, which were expected to involve computer simulations and not troops or equipment.

The North’s Foreign Ministry said Tuesday the drills “compelled (North Korea) to develop, test and deploy the powerful physical means essential for national defense.”