The United States will take "whatever steps" it can to hold to account those involved in arms transfers between North Korean and Russia, the State Department said Thursday, stressing it will "closely" monitor related developments.

Matthew Miller, the department's spokesperson, made the remarks after the US government revealed last Friday that the North shipped 1,000 containers of military equipment and munitions to Russia in recent weeks for use in Ukraine.

"We have released information to show that military assistance is already moving from DPRK into Russia," Miller told a press briefing, using the acronym for the North's official name, the Democratic People's Republic of Korea.

"We will closely monitor that and we will take whatever steps we can to hold the parties to account as we have in the past," he added.

The spokesperson stressed that a reason why Russia has "had to go around the world looking for arms" is because of sanctions and export controls imposed by the US.

"One of those states is the DPRK," he said.

Seoul and Washington have said that any arms trade with North Korea would be in violation of multiple UN Security Council resolutions that Moscow itself voted to adopt. (Yonhap)