The Belgian authorities have banned a gathering of far-right activists, due to be held on Sunday, May 5 in the Anderlecht area of Brussels.
Critics had slammed the planned event as “anti-semitic”.
Anderlecht mayor Eric Thomas said the congress was being prohibited as there were “clearly risks to public order”.
Event organiser, MP Laurent Louis, denied the accusations of anti-semitism surrounding the event.
Controversial French comedian Dieudonné, who has been convicted of anti-Jewish hate speech, had been among those expected to attend.