The Kremlin said on Tuesday there was "no proof" North Korea was sending supplies of weapons to Russia, after Washington released images purportedly showing arms shipments from Pyongyang.
North Korean leader Kim Jong Un traveled to Russia last month and met President Vladimir Putin, sparking speculation among Western countries over the possibility of a potential arms deal.
"They report this all the time, without providing any proof," Kremlin spokesman Dmitry Peskov told Russian news agencies when asked about the reported arms shipments.
The White House said on Friday that North Korea had already delivered over 1,000 containers of military equipment and munitions to Russia in recent weeks for use in Ukraine.
While Russia said no agreements were signed during Kim's visit in September, Putin said he saw "possibilities" for military cooperation.
Russian Foreign Minister Sergei Lavrov is expected to arrive in the reclusive country on Wednesday for a two-day visit. Details of the trip remain unclear.
Russia and North Korea, historic allies, are both under rafts of global sanctions — Moscow for its Ukraine offensive, and Pyongyang for its nuclear weapon tests.
North Korea, which the United States has previously accused of supplying shells to Russia's Wagner mercenary group, is a mass producer of conventional weaponry and is known to be sitting on large stocks of Soviet-era war material.