The governments of Poland and Ukraine are facing a new diplomatic dispute after President Volodymyr Zelensky approved a Ukrainian military unit’s request to carry the honorary name “Heroes of the Ukrainian Insurgent Army,” or UPA.

The move drew a sharp response in Warsaw, where the UPA is associated with World War II massacres of Polish civilians. Poland recognizes these massacres as genocide. Polish President Karol Nawrocki moved to revoke Zelensky’s Order of the White Eagle, the country’s highest state honor, while Zelensky returned the medal and said no one would dictate which heroes Ukrainians choose to honor.