North Korea has successfully conducted ground tests of newly developed solid-fuel engines for a new type of intermediate-range ballistic missile, Pyongyang's state media said Wednesday.

The first- and second-stage engines were tested Saturday and Tuesday to evaluate the technical specifications of the newly developed high-thrust solid-fuel IRBM engines, the Korean Central News Agency said.

"The first ground jet tests of the first- and second-stage engines were very successful and the reliability and stability of the already-established Korean-style high-thrust solid-fuel engine designing and manufacturing technologies were clearly verified once again," the KCNA said.

"The test provided a sure guarantee for reliably accelerating the development of the new-type IRBM system," it said.

The KCNA said the North's General Missile Bureau attached "great significance" to the development at a time the country faces a "grave and unstable security environment" and "vicious" military collusion among its enemies.

Despite international condemnation, the North has been seeking to bolster its nuclear and missile capabilities that are banned under UN Security Council resolutions.

Earlier this month, the North designated a "missile industry day" to mark the anniversary of its test-firing of the Hwasong-17 intercontinental ballistic missile last year.

The North is also believed to be preparing to launch a military spy satellite, apparently with technological assistance from Russia following a rare summit between North Korean leader Kim Jong-un and Russian President Vladimir Putin in September.

After two earlier launches failed in May and August, the North said it would try again in October. But no such launch has happened, and the North has given no word as to why the launch has been postponed and when it will take place. (Yonhap)