U.S. State Secretary Antony Blinken expressed his concern about the growing military cooperation between Russia and North Korea during a visit to South Korea on Nov. 9.
His comments came during a joint press conference with South Korean Foreign Minister Park Jin.
The military ties are increasingly a "two-way street," in which North Korea provides Russia with military equipment to use in Ukraine. In turn, Russia offers military technology and assists with North Korea's long-range attack capabilities, potentially including ballistic missiles and nuclear technology, according to Blinken.
Speaking on a trip to Asia that includes stops in Japan and India, Blinken emphasized that the military ties between Russia and North Korea are not just a potential threat to their respective neighbors but also to the "global non-proliferation regime."
With Russia's military stocks running low and domestic production capacity simultaneously hampered by Western sanctions, it has increasingly turned to other sources for military equipment, including North Korea.
Russia and North Korea signed a widely condemned arms deal in October, which Russia has denied.
Nonetheless, U.S. National Security Council spokesperson John Kirby said on Oct. 13 that Russia had received shipments of North Korean weapons and ammunition following a meeting between Russian dictator Vladimir Putin and North Korean leader Kim Jong Un in September.
Russian Foreign Minister Sergei Lavrov thanked North Korea for its "fundamental, unequivocal support" in the war against Ukraine on Oct. 18 during a visit to the country.