How Ukraine should respond to the invasion of DPRK troops: Biden made a statement.

U.S. President Joe Biden stated that Ukraine must respond if North Korean soldiers cross its borders. This was reported by Reuters.

If they cross Ukraine's borders, yes

The American president also expressed his concern that North Korean troops are already in Russia's Kursk region.

According to CNN, there are already a small number of DPRK soldiers on Ukrainian territory.

NATO Secretary General Mark Rutte confirmed Russia's involvement of North Korean military in the war against Ukraine.

According to President Volodymyr Zelensky, intelligence indicates that the first DPRK military will be deployed by Russia in combat zones.

North Korean factories are working at full capacity to supply Russia's armed forces.

According to the official publication The Wall Street Journal, DPRK military in Russia may be young and inexperienced soldiers.