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.

North Korean soldiers previously fighting alongside Russia's army on the Kursk front line appear not to have been engaged in combat since mid-January, South Korea's spy agency told AFP on Tuesday, after Ukraine claimed they had been withdrawn following heavy losses.

"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 ballistic missiles fired at Ukraine by Russian forces since late December have been far more precise than salvos of the weapons launched over the past year, two senior Ukrainian sources told Reuters.

Ukraine is fighting a war against two nuclear weapons countries: Russia, a signatory of the non-proliferation treaty, and North Korea, which is not. Since 2014, Moscow has been undermining the logic and letter of the Nuclear Non-Proliferation Treaty (NPT) with its nuclear posturing.

This is almost certainly primarily due to heavy losses sustained during attacks against Ukrainian-held positions.” Reports differ on the scale of the losses but one put them as high as 4,000 North Korean soldiers killed or wounded.

The Ambassador of Ukraine to South Korea, Dmytro Ponomarenko, declared Kyiv's readiness to transfer North Korean soldiers captured in the Kursk region to Seoul. The Ambassador of Ukraine to South Korea,

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,