Russia is deploying “human waves” of North Korean soldiers, the U.S. said Friday, and at least one soldier captured by Ukraine died of his injuries.

According to White House National Security Council spokesperson John Kirby, some North Korean soldiers have taken their own lives rather than surrendering to Ukrainian forces.

These suicides, he said, were “likely out of fear of reprisal against their families in North Korea in the event that they’re captured.”

South Korea’s National Intelligence Agency had confirmed on Friday that the North Korean soldier captured the previous day had died.

Ukrainian President Volodymyr Zelenskyy said in a statement on Telegram Friday that at least 3,000 North Korean soldiers have died or been wounded in Russia’s Kursk region, where Ukrainian forces mounted a lightning incursion in August.