Ukraine has worked for years through legislation and military restructuring to contain a fringe far-right movement whose members proudly wear symbols steeped in Nazi history and espouse views hostile to leftists, L.G.B.T.Q. movements and ethnic minorities. But some members of these groups have been fighting Russia since the Kremlin illegally annexed part of the Crimea region of Ukraine in 2014 and are now part of the broader military structure. Some are regarded as national heroes, even as the far-right remains marginalized politically.

The iconography of these groups, including a skull-and-crossbones patch worn by concentration camp guards and a symbol known as the Black Sun, now appears with some regularity on the uniforms of soldiers fighting on the front line, including soldiers who say the imagery symbolizes Ukrainian sovereignty and pride, not Nazism.

In the short term, that threatens to reinforce Mr. Putin’s propaganda and giving fuel to his false claims that Ukraine must be “de-Nazified” — a position that ignores the fact that Ukraine’s president, Volodymyr Zelensky, is Jewish. More broadly, Ukraine’s ambivalence about these symbols, and sometimes even its acceptance of them, risks giving new, mainstream life to icons that the West has spent more than a half-century trying to eliminate.

“What worries me, in the Ukrainian context, is that people in Ukraine who are in leadership positions, either they don’t or they’re not willing to acknowledge and understand how these symbols are viewed outside of Ukraine,” said Michael Colborne, a researcher at the investigative group Bellingcat who studies the international far right. “I think Ukrainians need to increasingly realize that these images undermine support for the country.”

In a statement, the Ukrainian Defense Ministry said that, as a country that suffered greatly under German occupation, “We emphasize that Ukraine categorically condemns any manifestations of Nazism.”