The North Koreans fought alongside Russia’s 810 Separate Naval Infantry Brigade, the official added, the New York Times reports.
North Korean soldiers have joined Russia’s war against Ukraine, marking their first clash with Ukrainian forces in the Kursk region, a key area of Russian-held territory, according to Ukrainian and U.S. officials.
The Ukrainian official described the engagement as limited, likely intended to test the Ukrainian defences for weaknesses.
The North Koreans fought alongside Russia’s 810 Separate Naval Infantry Brigade, the official added, the New York Times reports.
The exact timing of the clash remains unclear, and no details on casualties have been provided by the Ukrainian official.
However, the U.S. official confirmed that a significant number of North Korean troops were killed.
Both officials spoke on the condition of anonymity to share sensitive military information.
The North Korean troops are part of an estimated contingent of 10,000 soldiers sent by Kim Jong-un to assist Russian forces in pushing back Ukrainian forces from the Kursk region, which Ukraine has controlled since an incursion began last summer.
Although the majority of North Korean forces have not yet seen combat, their deployment is being viewed by both Ukrainian and Western officials as a major escalation after more than two years of conflict.
In a nightly address, President Volodymyr Zelensky appeared to confirm the presence of North Korean troops, urging Ukraine’s allies to assist in confronting this new threat.
“The first battles with North Korean soldiers mark a new chapter of global instability,” he said. “Together with the world, we must do everything to ensure that this Russian step toward expanding the war — this true escalation — becomes a loss.”
The North Korean troops arrived in Russia’s Vladivostok last month by boat, before making the 4,000-mile journey west to Kursk. The Ukrainian official indicated that the remainder of the force could soon enter combat.
These troops have been divided into two units, one composed of assault forces and the other of support troops tasked with securing territory recaptured from Ukrainian forces.
The strategic significance of these North Korean troops has sparked debate among Ukrainian officials and their allies. Some view their involvement as a desperate move by Russian President Vladimir Putin, whose forces have suffered heavy losses in eastern Ukraine.
Others believe the deployment is aimed at showing that Russia remains far from isolated and to weaken Western resolve. The presence of North Korean troops could also allow Russia to divert forces to offensive operations in the Donbas region as winter approaches.
It remains unclear what, if anything, President Putin promised Kim in return for sending troops. U.S. officials have found no evidence of a quid pro quo but are concerned that Russia could provide significant military assistance to North Korea, further escalating the threat to both North Korea’s neighbours and the United States.
In addition to sending troops, North Korea has reportedly supplied Russia with 16,000 shipping containers of artillery shells, rockets, and missiles since the summer of 2023. In June, Putin met with Kim in Pyongyang, where they renewed a Cold War-era defence and military cooperation treaty.