People watch TV at Seoul Railway Station (South Korea) a North Korean missile test launch, September 25. Photo: AFP/VNA

The JCS said it detected launches from the Sunan area in Pyongyang between 6:10 p.m. and 6:20 p.m. local time. "Our military will maintain a firm readiness posture based on the capabilities to respond overwhelmingly to any North Korean threats while tracking and monitoring related movements in close coordination with the US," the JCS added.

Earlier, the JCS said North Korea had launched an unidentified ballistic missile into the East Sea. The Japanese government confirmed that Pyongyang launched what appeared to be a ballistic missile.

The launch came just three days after North Korea launched a short-range ballistic missile off its east coast and a day before US Vice President Kamala Harris is scheduled to visit South Korea.