North Korea Shipped Arms to Russia for Use in Ukraine, U.S. Says

North Korea shipped more than 1,000 containers of arms to Russia in recent weeks for use in the war in Ukraine, U.S. officials said on Friday, the latest example of Moscow scouring the world to replenish its depleted stores of weapons from some of the most isolated outlaw nations.

American intelligence agencies tracked the shipment of military equipment and munitions as it made its way from North Korea on a Russian-flagged ship to a Russian port and from there by rail to an ammunition depot not far from Ukraine, officials said.

“We condemn the D.P.R.K. for providing Russia with this military equipment, which will be used to attack Ukrainian cities, kill Ukrainian civilians and further Russia’s illegitimate war,” said John F. Kirby, a spokesman for the White House National Security Council, using the initials for North Korea’s formal name, the Democratic People’s Republic of Korea.

Mr. Kirby gave no details about the nature of the munitions but said the White House was especially concerned that Russia would repay North Korea by providing it more sophisticated weapons and technology it otherwise would not have available under international sanctions. American intelligence agencies have concluded that North Korea has requested fighter aircraft, surface-to-air missiles, armored vehicles, ballistic missile production equipment and other materials and advanced technologies.

The agencies have not determined whether Russia has granted the requests but have detected Russian ships offloading unknown materials in North Korea, Mr. Kirby said. He added that such shipments would violate United Nations resolutions and said the United States would raise the matter with the United Nations.

“This expanding military partnership between the D.P.R.K. and Russia, including any technology transfers from Russia to the D.P.R.K., undermines regional stability and the global nonproliferation regime,” Mr. Kirby said.

The disclosure by the White House came as President Biden is pushing Congress to approve more military aid to Ukraine. His $24 billion request has been held up by opposition from hard-right House Republicans, but White House officials said the president would send a new supplemental spending request to Congress next week.

The White House hopes to bypass opposition to Ukrainian aid by linking it to additional aid to Israel following the devastating terrorist attack by Hamas last weekend that killed more than 1,300 people, including at least 27 American citizens. Republicans are more supportive of aid to Israel, possibly making a joint package more palatable. Some in Congress have talked about adding aid to Taiwan and money for American border protection to the package to draw more support.

With its own military industry unable to keep up with the need for munitions in Ukraine, Russia has already turned to suppliers like Iran, which has provided attack and surveillance drones. A weapons research group recently reported that Russia seems to be replicating the Iranian Shahed-136 drones and using them in Ukraine.

American officials have been concerned for some time about the prospect of North Korea arming Russian forces. North Korea has a vast supply of Soviet-era weaponry that could be easily integrated into Russian military operations. Kim Jong-un, North Korea’s leader, visited the Russian Far East last month and met with President Vladimir V. Putin, which was seen as a sign of a closer alignment between the two nations.

Gen. Mark A. Milley, before stepping down two weeks ago as chairman of the Joint Chiefs of Staff, said he anticipated North Korea providing Soviet-era 152-millimeter artillery rounds to Moscow, but added he was not persuaded that it would have a critical impact on the Ukraine war.

“Would it have a huge difference? I’m skeptical of that,” General Milley told reporters last month. While adding that he did not want to play down such aid, he said “I doubt that it would be decisive.”

On Friday, the White House released photos of what it said was one shipment of arms that evidently began shortly before the meeting between Mr. Kim and Mr. Putin.

About 300 shipping containers were spotted being staged at Najin, North Korea, on Sept. 7 and 8, according to the White House account. The shipment was transported on the Russian-flagged M/V Angara to Dunay, Russia, on the Sea of Japan, where it arrived on Sept. 12, the day before the Putin-Kim meeting. Additional containers were prepared for delivery back to North Korea.

The containers from North Korea were then moved by rail across the expanse of Russia to the ammunition depot in the southwestern region of the country, near Tikhoretsk, about 180 miles from the Ukrainian border, arriving on Oct. 1, according to the U.S. intelligence.