North Korea leader Kim Jong Un attended and oversaw the test launch of a brand new intermediate-range sold fuel missile that carried a hypersonic warhead on Tuesday, the country’s official state media was cited as saying by Kyodo News.

According to Korean Central News Agency Kim Jong Un, attended the test launch of the solid fuel-powered Hwasong-16 missile in a Pyongyang suburb and claimed all missiles his country has developed are now based on solid fuel technology and are capable of carrying nuclear warheads.

North Korea launched a ballistic missile toward the Sea of Japan on Tuesday, with the projectile falling into waters outside Japan’s exclusive economic zone, according to the Japanese Defence Ministry. The South Korean military said the projectile might have been a hypersonic weapon. Hypersonic missiles are designed to travel at more than five times the speed of sound on irregular and low-altitude trajectories. Solid-fuel missiles do not need to be filled up with fuel before being launched like liquid-fuel missiles do, making it harder for other countries to detect launch preparations and enhancing their pre-emptive strike and retaliatory capability, Kyodo News reported.

North Korea said in January it had test-fired an intermediate-range ballistic missile carrying a hypersonic warhead, and said last month that it had successfully conducted a grounded test of a solid-fuel jet engine for an intermediate-range hypersonic missile.

During Tuesday’s test, the hypersonic warhead reached its first peak at a height of 101.1 kilometers and the second at 72.3 km while making a 1,000-km-long flight as scheduled to accurately hit waters in the Sea of Japan, according to KCNA. The Japanese Defence Ministry had said the missile flew over 650 km. The test-fire had no adverse effect on the security of neighbouring countries, the news agency said.

According to the Kyodo News report, Kim expressed great satisfaction over the test-fire result and said his country has perfected the project for “putting all the tactical, operational and strategic missiles with various ranges on solid-fueled, warhead-controlled and nuclear warhead-carrying basis.” He noted the current “epoch-making success serves as a special event in which a great change will be brought about in enhancing the nuclear war deterrent” of North Korea’s armed forces, according to KCNA.