SEOUL (REUTERS) - North Korean leader Kim Jong Un said the launches of tactical guided missiles on Tuesday were a warning to the United States and South Korea's joint military drills, state media KCNA said on Wednesday (Aug 7).

US national security adviser John Bolton reminded North Korea on Tuesday of its leader's pledge to President Donald Trump not to resume launches of intercontinental-range missiles after Pyongyang conducted its fourth short-range missile test in less than two weeks and warned it might pursue "a new road".

Mr Kim said the military action was "an occasion to send an adequate warning to the joint military drill now underway by the US and South Korean authorities", according to KCNA.

The "new-type tactical guided missiles", launched from the western area of North Korea, flew across the peninsula "over the capital area and the central inland region" to "precisely hit the targeted islet" in the sea off the east coast of the country, KCNA said, confirming the South Korean military's report of their trajectories on Tuesday.

The launches "clearly verified the reliability, security and actual war capacity" of the weapon, KCNA said, echoing analysts who said the launches showed North Korea's confidence in its missile technology.

The US and South Korea kicked off their largely computer simulated Dong Maeng exercises this week, which means "alliance", as an alternative to previous large-scale annual drills that were halted to expedite denuclearisation talks.

North Korea decry those exercises as a rehearsal for war aimed at toppling the regime.

"South Korea and the United States have downscaled, refocused, rescheduled and quietly conducted their combined exercises to allow space for diplomacy with North Korea," said Mr Leif-Eric Easley, who teaches international security at Ewha University in Seoul.

"But Pyongyang shows no appreciation for this, keeping its own exercise schedule unchanged, conducting provocative weapons tests, and dialling up its rhetoric."

The negotiations are yet to restart after being stalled since a second summit between Mr Trump and Mr Kim broke down in February, though the two agreed to revive them during their off-the-cuff meeting in June at the inter-Korean border.

US Defence Secretary Mark Esper, who arrived in Tokyo on Wednesday as part of his first Asia tour since taking office, said his country won't "overreact" to the missile tests.

US national security adviser John Bolton on Tuesday highlighted Mr Kim's pledge to Mr Trump not to resume tests of intercontinental-range missiles that threaten the US.