North Korean leader Kim Jong Un supervised the launch of "a new type of tactical guided weapon" as a "solemn warning" to the South, state media said Friday, a day after the North fired two missiles into the sea.
Kim personally organised and guided the firing of the "state-of-the-art weaponry system" on Thursday and was "gratified" with the outcome, KCNA said.
It was Pyongyang's first missile test since an impromptu June meeting between Kim and US President Donald Trump in the demilitarised zone between North and South Korea.
That meeting produced an agreement to resume a working-level dialogue on denuclearisation with Washington but those talks have yet to begin.
The North has previously warned that upcoming US-South Korea joint military exercises could affect the resumption of the talks.
There are close to 30,000 US troops stationed in South Korea and their annual manoeuvres with South Korean soldiers have always infuriated Pyongyang.
Japan's defence minister called the launches "extremely regrettable" while Seoul's National Security Office said it expressed "strong concern" and the US called for an end to such "provocations".
Kim accused the South of "double-dealing behaviour" by talking peace, but then "behind the scene, shipping ultra-modern offensive weapons and holding joint military exercises", KCNA said.
South Korea's leaders "should not make a mistake of ignoring the warning from Pyongyang", it added.
Seoul's Joint Chiefs of Staff (JCS) said the two missiles were launched just after dawn from Wonsan on the east coast.
A military official in Seoul said one of the two weapons flew more than 430 kilometres (270 miles), while the other travelled 690 kilometres.
Seoul's National Security Office said the launches were of a "new type of short-range ballistic missiles".
The US said it wanted to continue talking with the North but called for a halt to such "provocations".
"We want to have diplomatic engagement with North Korea, and we continue to urge the North Koreans to resolve all the things that the president and Chairman Kim have talked about through diplomacy," US State Department spokeswoman Morgan Ortagus said.
"We urge no more provocations, and that all parties should abide by their obligations under (United Nations Security Council) resolutions," she said.
Japan's defence minister stressed that the missiles had fallen short of his country's exclusive economic zone.
Pyongyang carried out similar short-range launches in May, which Trump dismissed at the time as "very standard stuff" that would have no impact on his relationship with Kim.
Thursday's launches came a day after US National Security Advisor John Bolton -- an arch-hawk regularly vilified by North Korean state media -- spoke with senior South Korean officials in Seoul.