The British defense ministry said it is "almost certain" that North Korean munitions have reached ammunition depots in western Russia, in support of the Russian military's operations in Ukraine.
The ministry revealed the assessment on the social media platform X on Thursday, adding that if the North sustains the recent scale and pace of military-related shipments, it could become one of Russia's "most significant foreign arms suppliers, alongside Iran and Belarus."
Earlier this month, the White House claimed that Pyongyang had transported over a thousand containers of military supplies to Russia, an assertion that Moscow has since denied.
The British ministry said while it is unclear what Russia may have agreed to provide North Korea in return, there seems to be a possibility that two sides have reached a comprehensive agreement.
The ministry added that high-level Russian officials who had recently visited Pyongyang could have proposed financial compensation, economic aid, military technology provision, or cooperation in space and other cutting-edge technologies.
This was an apparent reference to Russian foreign minister Sergei Lavrov's visit to the North last week, and a visit by defense minister Sergei Shoigu in July.