North Korean troops fighting alongside the Russian military to reclaim the Ukrainian-occupied area of Kursk are suffering heavy losses, the Ukrainian secret service said on Wednesday.

Citing wiretapped phone conversations, Ukraine’s SBU domestic intelligence agency said more than 200 injured North Koreans have been admitted to a hospital near Moscow within a few days.

There are complaints that the foreign troops are receiving preferential treatment in hospital, the SBU added.

The SBU’s information could not be independently verified.

Ukrainian President Volodymyr Zelensky has repeatedly spoken of high losses among North Korean soldiers in recent days and has accused Russia of cremating dead soldiers to conceal the death toll.