Ukrainian special operations forces have given an insight into the brutal, near-suicidal tactics of the North Koreans they have faced in intense fighting in the Russian border region of Kursk.

Weapons and notes left on dead North Korean troops in Russia give Ukraine a glimpse into their mindset — and show how they are quickly adapting to modern war.

All North Korean recruits are taught a song that includes a verse about saving their last bullet for themselves to avoid capture, one former soldier told NBC News.

Troops from North Korea appear to have fallen back from Russia's frontline after suffering heavy losses when engaging Ukrainian forces.