North Korean Foreign Minister Choe Son-hui, right, and her Russian counterpart, Sergei Lavrov, shakes hands to each other, Pyongyang, Oct. 18, 2023. Yonhap

Deepening cooperation between North Korea and Russia is a trend of "great concern," a State Department spokesperson said Sunday, as North Korea's top diplomat is set to visit Russia this week in a sign of growing bilateral ties.

North Korean Foreign Minister Choe Son-hui is scheduled to visit Russia from Monday through Wednesday at the invitation of Russian Foreign Minister Sergei Lavrov, according to the North's official Korean Central News Agency.

"Deepening cooperation between Russia and the DPRK is a trend that should be of great concern to anyone interested in maintaining peace and stability on the Korean Peninsula, upholding the global nonproliferation regime, and supporting the people of Ukraine as they defend their freedom and independence against Russia's brutal invasion," the spokesperson said in response to a question from Yonhap News Agency.

DPRK stands for the North's official name, the Democratic People's Republic of Korea.

Choe's trip to Russia came amid concerns about alleged arms transfers between the North and Russia that Washington, Seoul and other governments have decried as a violation of multiple U.N. Security Council resolutions.

Earlier this month, the White House said the North had provided Russia with several dozen ballistic missiles, some of which were used against Ukraine on Dec. 30, 2023, Jan. 2 and Jan. 6.

In October 2023, the White House also revealed that the North had delivered more than 1,000 containers of military equipment and munitions to Russia for use in Ukraine.

The transaction came amid persistent speculation that the Sept. 13, 2023 summit between North Korean leader Kim Jong-un and Russian President Vladimir Putin at a Russian spaceport might have led to an arms deal. (Yonhap)