Russia acknowledged for the first time that North Korean troops were on the front lines of its war with Ukraine, with a senior military official crediting their role in helping Russian forces reclaim control of the Kursk region.

“I would like to separately note the participation ... of military personnel of the Democratic People’s Republic of Korea,” Valery Gerasimov, the Russian chief of general staff, told Russian President Vladimir Putin in a report Saturday.

Gerasimov added that under a “comprehensive, strategic partnership” between the two countries, North Korean soldiers had provided “significant assistance” to Russia’s army in defeating Ukrainian forces.

Putin congratulated his military in a statement from the Kremlin on Saturday, adding that “the full defeat of the enemy in the Kursk border region creates conditions for further successful actions by our forces on other important parts of the front.”

South Korean media reported this year that more than 11,000 North Korean troops were fighting in the western Russian region of Kursk, reports that neither Moscow nor Pyongyang had confirmed until now.

In March, South Korean officials reported that between January and February, North Korea had sent an additional 3,000 troops to Russia after around 4,000 of them were “believed to have been killed or injured” due to inexperience in drone warfare.

Shortly after the Trump administration temporarily suspended military and intelligence assistance to Kyiv in March, Russian forces intensified their attacks on Ukrainian troops in the territory.

Ukraine has not yet responded to Putin’s claim, but losing control of the western Russian region would be a significant blow for Kyiv, which Ukrainian President Volodymyr Zelenskyy has viewed as valuable leverage in any future peace talks.