Here is how the Russians moved all the arms they received from North Korea into Russia for further movement to the battlefields of Ukraine:

This image, provided by the U.S. government, shows apparent arms transfers between North Korea and Russia. (Yonhap)
Two Russian ships made at least five round trips between North Korea and Russia, beginning mid-August, in what could be arms transfers, the Washington Post reported Monday, citing satellite imagery.
Based on analysis by the Royal United Services Institute (RUSI), a London-based think tank, the ships have been travelling between the northeastern North Korean port of Najin and a port facility in Dunay in Russia’s Far East between mid-August and Saturday.
The analysis came after the U.S. government revealed Friday that the North shipped more than 1,000 containers of military equipment and munitions to Russia in recent weeks for use in Ukraine, highlighting burgeoning military cooperation between Pyongyang and Moscow.
Yonhap
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