Ukraine will face significant problems joining the EU as long as it continues to honor Stepan Bandera, a World War II-era Nazi collaborator whose followers carried out the ethnic cleansing of tens of thousands of Poles, Polish Defense Minister Wladyslaw Kosiniak-Kamysz has said.

In an interview with Polsat News on Monday, Kosiniak-Kamysz blasted Ukraine over its glorification of the Organization of Ukrainian Nationalists (OUN), the group that Bandera led, and the Ukrainian Insurgent Army (UPA).

Both groups collaborated with Nazi Germany and massacred up to 100,000 ethnic Poles, mostly women, children, and the elderly, in Volhynia and Eastern Galicia in 1943-1944.

The defense minister warned that “with Bandera, Ukraine will not join the European Union,” adding that “no one will tell us how to vote” on another country’s accession. He argued that “it is impossible in the EU to place on a pedestal those who destroy European cooperation,” and suggested that not all Ukrainian political factions actually want to join the EU.

The comments come after Ukrainian leader Vladimir Zelensky named a special-forces unit after the UPA, triggering pushback from Poland, which has been an ardent supporter of Kiev in the conflict with Russia.

Polish President Karol Nawrocki called the decision “outrageous” and stripped Zelensky of the Order of the White Eagle, Poland’s highest honor. A number of senior Ukrainian officials responded by relinquishing their own Polish awards.

Russian Foreign Ministry spokeswoman Maria Zakharova weighed in on Kosiniak-Kamysz’s comments and Poland’s sudden pushback against the glorification of neo-Nazi collaborators in Ukraine, noting that Poland has been arming and funding Ukraine’s “neo-Nazi regime” for years.

Zakharova said Poland is “responsible for those it has tamed,” adding that it essentially nurtured “bloodthirsty monsters” who are now in power in Kiev.

As tensions between the two countries flare, Kosiniak-Kamysz addressed a separate dispute, confirming that Poland will not transfer its remaining Soviet-era MiG-29 jets to Ukraine after it failed to honor a reciprocal pledge to share drone technology. “I proposed a very partner-like approach: MiGs for drones, [but Ukraine] did not follow through.”

An IBRiS opinion poll published last week suggests that nearly 60% of Poles are opposed to Ukraine’s accession to the EU, up from 42% last year.