The missiles, dubbed the KN-23, are designed to evade missile defence systems by being easier to hide, launch, and manoeuvre in flight, experts said.
The launches came six days after North Korea fired two short-range ballistic missiles that Seoul officials say flew 600 kilometres before landing off the North’s east coast.
The latest launches also came hours after a senior US official said President Donald Trump has sent mementos from his brief visit to North Korea last month to Kim.
The official said a top staffer from the National Security Council hand-delivered photographs from the Trump-Kim meeting in June at the demilitarised zone to a North Korean official last week. The Trump administration official spoke on the condition of anonymity because the official wasn’t authorised to speak publicly.
Diplomacy between North Korea and the US remained deadlocked since the second Trump-Kim summit in Vietnam in February ended without any agreement.
The summit fell apart after Trump rejected Kim’s demand for widespread sanctions relief in return for dismantling his main nuclear complex, a partial disarmament step.
North Korea’s state media said leader Kim Jong-Un supervised a test of a new missile Thursday designed to deliver “solemn warning” to South Korea over its purchase of high-tech US-made fighter jets and its plans to conduct military drills that Pyongyang sees as an invasion rehearsal.
South Korea’s military said the flight data of the weapon launched on Thursday showed similarities to the Russian-made Iskander, a short-range, nuclear-capable missile.