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.

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.

In an interview with the Associated Press on Feb. 2, Zelensky added that while these countries had previously cooperated on weapons and technology, they are now openly engaged in Russia’s war against Ukraine.

A Ukrainian news outlet has published a video showing the capture of a North Korean soldier, as South Korea's spy agency said Kim Jong Un has pulled troops from Russia's Kursk region. Newsweek has contacted the Russia's Foreign Ministry for comment.

A North Korean soldier captured fighting for Russia in Ukraine last month reportedly made just two requests to his captors - one for water and another for a cigarette

One Ukrainian special forces soldier shares details of how his team captured the North Korean, giving an insight into the North Korean mindset.