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.

New reports reveal the presence of North Korean soldiers on the Kursk front, using outdated strategies and extreme loyalty to Kim Jong Un.

The drone blew out a wall and surrounding windows in the building in Sumy, a major city, just after 1 a.m., the Sumy regional administration said.

The Ukraine conflict is the first major drone war in military history. Despite tactical losses on several parts along the line of contact, the Ukrainian military has continued to maintain strategic pressure on Russia by targeting and attacking major targets behind enemy lines.

An overnight Russian drone attack on Ukraine killed at least four people in the northeastern city of Sumy, Ukraine's Interior Ministry said. Images shared by emergency services showed a gaping hole ripped into the side of an apartment building in Sumy and rescue workers digging through debris as they searched for survivors.