Ukraine’s President Volodymyr Zelensky said Friday that several “seriously wounded” North Korean soldiers died from their injuries after being captured by Ukrainian forces.

For years, North Korea’s military has helped its leader, Kim Jong-un, keep control of his people and provide a buffer against the country’s sworn enemy, South Korea. With 1.3 million members, the North’s army is among the world’s largest conventional armed forces.

White House National Security communications adviser John Kirby said Russia was treating North Korean troops as “expendable” by sending them on impractical ground operations in its war against