North Korean troops deployed in Russia’s Kursk region are suffering heavy casualties and are left unprotected by Russian forces fighting alongside them, Ukrainian President Volodymyr Zelensky said on Friday.

Zelensky said in a video that Russian troops are sending the North Koreans into battle with minimal protection and are taking extreme measures to avoid being captured.

“Their losses are significant, very significant. We see that neither the Russian military nor their North Korean supervisors have any interest in ensuring the survival of these North Koreans,” he said.

“Everything is set up so that it is impossible to capture them. There are cases in which they are executed by their own forces. The Russians send them on attacks with minimal protection.”

Ukrainian and Western intelligence agencies say there are about 12,000 North Korean troops in Kursk, a Russian border region where Ukrainian forces have seized territory since the August invasion.

Earlier this week, Zelensky said more than 3,000 North Koreans had been killed or wounded.

The Ukrainian president said that Ukrainian forces managed to capture some North Korean soldiers “but they were seriously injured and it was not possible to rescue them.”

Zelensky said the Korean people “should not lose their lives fighting in Europe. This is something that Korea’s neighbors, including China, can influence.”

“If China is sincere in its statements that the war should not be extended, it must put appropriate pressure on Pyongyang.”