The presence of North Korean soldiers alongside Russians fighting Ukraine raises many tactical and military questions, leading some analysts to wonder about their effectiveness and ultimate objectives.

North Korea had never sent troops into combat abroad before, primarily out of fear that they might defect or make unflattering comparisons between foreign armies and their own.

"The regime is worried that soldiers from the isolated country might pick up 'incorrect' ideas," wrote Fyodor Tertitskiy, a researcher at Seoul's Kookmin University.