The move represents an unprecedented escalation in Russia's war against Ukraine."Today, we already have preliminary data that the Russians have begun to use North Korean soldiers in their assaults — a significant number of them," Zelensky said in a video address."The Russians include them in combined units and use them in operations in Kursk Oblast."North Korean troops have not yet joined Russian forces in any other areas of the front, but this could change, Zelensky said. Zelensky also reported that North Korean units have sustained "noticeable losses." Russian President Vladimir Putin has "dragged another state into this war," Zelensky said."And if this is not escalation, then what is the escalation that so many have been talking about?" The first clashes between North Korean and Ukrainian troops in Kursk Oblast were reported in early November.