Spanish police are on red alert as scores of Eintracht Frankfurt hooligans are set to march to the stadium ahead of Rangers' Europa League Final.
Frankfurt casuals attacked West Ham fans after the German side dumped their English counterparts out of the competition.
The Bundesliga club are expected to take around 18,000 fans to the Estadio Ramón Sánchez-Pizjuán.
And cops in Spain have been briefed to look out for any trouble in the Andalusian city.
A Rangers insider said: "Police are more concerned about the Frankfurt fans than the Rangers fans.
"There's over 100 identified high-risk category Frankfurt supporters going, and they're marching to the stadium, which creates a problem for ticketed fans and non ticketed fans.
"We are confident in UEFA and the police's operation, if it plays out as planned."
Another club insider added: "The big issue is the Eintracht Frankfurt supporters and the issues they've been having in Europe with violence."
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