Russia is planning to send first North Korean soldiers to a combat zone on Oct. 27-28, President Volodymyr Zelensky said on Oct. 25, citing intelligence reports.

Speaking after a meeting with the Headquarters of the Supreme Commander-in-Chief, Zelensky called it an “obvious step toward escalation” that stands in contrast to “disinformation we heard from the Kremlin in recent days.”

“The world can clearly see what Russia really wants, and that is to continue the war. That is why we need a principled and strong reaction from the world’s leaders,” Zelensky said.

The president called on the West to put “tangible pressure” on both Moscow and Pyongyang to comply with the U.N. Charter and punish escalation.

North Korea has sent nearly 12,000 troops to Russia, including 500 officers and three generals, Ukraine’s military intelligence (HUR) said.

The first soldiers to participate alongside Russian forces in the war against Ukraine have been reportedly sent to Kursk Oblast, where Ukraine began a cross-border incursion in August and still holds significant swathes of territory.

Zelensky also said after the meeting that Ukraine had established a buffer zone in Kursk Oblast that prevents Russia from expanding the war to further Ukrainian territories in the east.

Following multiple reports by Ukraine and South Korea, the U.S. acknowledged that North Korean troops were arriving in Russia.

“What exactly they are doing – left to be seen,” said U.S. Defense Secretary Lloyd Austin, leaving room for doubt.

In return for the transfer of soldiers and arms, Russia is helping Pyongyang evade sanctions and develop its nuclear capabilities, according to HUR chief Kyrylo Budanov.