Though North Korean ballistic missiles account for only a small portion of Russia's missile strikes they carry a large warhead of up to one tonne and have a range of up to 800 km, the military source said. The Iskander-M, an equivalent Russian missile, carries a smaller payload and has a shorter range of 500 km.

When Ukrainian soldiers captured two North Korean prisoners of war last month, it provided the first undeniable proof of Pyongyang’s direct involvement in the war against Ukraine

"The worst problem we are facing is the one coming from North Korea," the head of Kyiv's military intelligence agency said in the fall.

North Korean missiles used by Russia in attacks on Ukraine since December have become more accurate, Reuters reported on Feb. 6, citing sources familiar with the matter. Analysts believe North Korea is using the battlefield as a testing ground for its missile technology,

North Korean ballistic missiles have been striking targets in Ukraine with increasing accuracy in recent weeks compared to over the past year — suggesting the Hermit Kingdom is using the battlefield as a testing ground for its new tech.

Experts say Pyongyang’s advancing missile technology raises global security risks and threatens regional stability.