North Korea on Friday said the missile used in its recent launch was its new solid-fuel "Hwasong-18" intercontinental ballistic missile, with leader Kim Jong-un claiming that the launch significantly improved its nuclear counterattack posture.

Kim guided Thursday's launch and said the new ICBM "radically promote the effectiveness of its nuclear counterattack posture and bring about a change in the practicality of its offensive military strategy," the North's official Korean Central News Agency reported in an English-language dispatch.

"The aim of the test-fire was to confirm the performance of the high-thrust solid-fuel engines for multi-stage missiles and the reliability of the stage-jettisoning technology and various functional control systems," the KCNA said.

"The test-fire confirmed that all the parameters of the new strategic weapon system fully met the requirements of the design in terms of accuracy," it said.

It said the missile's first stage landed in waters 10 kilometers off Kumya County, South Hamgyong Province, while the second stage fell into waters 335 km east of Orang County, North Hamgyong Province.

The North's leader also said Pyongyang will continue "offensive" actions so that its enemies suffer from "extreme uneasiness and horror," and proposed "important strategic tasks" to strengthen the country's nuclear force, the KCNA said, without elaborating.

Solid-fuel missiles are faster to shoot and harder to detect ahead of a launch.

On Thursday, South Korea's military said the North fired an intermediate- or longer-range ballistic missile that flew 1,000 kilometers before landing in the East Sea.

The latest launch comes just days ahead of the 111th birthday of the late Kim Il-sung, the North's national founder and the current leader's grandfather, on Saturday.

It also comes amid heightened tensions on the peninsula as the North has not responded to routine cross-border calls through inter-Korean liaison and military communication lines since last Friday.

Pyongyang has recently conducted other major weapons tests, such as what it claimed to be underwater nuclear attack drones. (Yonhap)