SEOUL, South Korea — 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.