Ukrainian President Volodymyr Zelensky said on Monday that more than 3,000 North Korean soldiers had been killed or wounded in Russia’s Kursk region and warned that Pyongyang could send more personnel and equipment to Moscow’s military.

“There are risks that North Korea will send additional troops and military equipment to the Russian military,” Zelenskyy said on Xu after receiving a report from his military commander-in-chief, Oleksandr Syrskyi.

“We will have tangible answers to that,” Zelenskyy said.

The estimate of North Korean losses is higher than that given by Seoul’s Joint Chiefs of Staff (JCS), which said on Monday that at least 1,100 North Korean soldiers had been killed or wounded.

The estimate is in line with a briefing last week by South Korea’s intelligence agency, which reported about 100 dead and another 1,000 wounded in the region.

Zelenskyy said that he provided preliminary data. Reuters could not independently verify reports of combat casualties.

Reports claim that 12,000 troops have already been sent

Russia has neither confirmed nor denied the presence of North Koreans on its side. Pyongyang initially dismissed reports of the troop deployment as “fake news,” but a North Korean official said any such deployment would be legal.

According to Ukrainian and allied estimates, North Korea has sent about 12,000 soldiers to Russia.

Some of them have been deployed to fight in Russia’s Kursk region, where Ukraine still holds a swath of land after a major cross-border incursion in August.

The JCS added that it had detected signs that Pyongyang was planning to produce suicide drones to supply to Russia, in addition to the 240mm multi-barrel rocket launchers and 170mm self-propelled howitzers already delivered.

Kiev continues to press allies for a tougher response as it says the transfer of wartime experience and military technology by Moscow and Pyongyang poses a global threat.

“For the world, the price of restoring stability is always much higher than the price of effective pressure on those who destabilize the situation and destroy lives,” Zelenskyy said.