Real Madrid have blocked Union Berlin fans from buying tickets online ahead of their Champions League clash.

All 3,840 tickets allocated to the German club were sold out in a few hours and Real have moved to block extra tickets being sold.

Many Union Berlin fans have tried to buy tickets for other parts of the ground through Real Madrid's official online ticket office. But Real have blocked their attempts.

Indeed, BILD says Union fans found thy were even blocked from visiting the club's online merchandise store.

It's suggested fans with a German IP on any device (computer, mobile, etc.) were automatically blocked from Real's connected websites.

Real have acted after last year's events at the Nou Camp as Eintracht Frankfurt fans filled the stadium to help their team defeat Barcelona in their Europa League quarterfinal.