Champions League: Heavy security for Madrid derby semi-final
More than 2,000 security officers will be on duty for Real Madrid's Champions League semi-final first leg with neighbours Atletico Madrid.
The tie at the Bernabeu on Tuesday has been classified as "high risk" and security will be "reinforced", the Madrid city government said on Friday.
Uefa ordered security at European games to be increased after the attack on the Borussia Dortmund team bus on 11 April.
Atletico will have 4,000 supporters at Real's 80,000-capacity ground.
Usually just a few hundred fans travel to away matches in Spain.
The number of security personnel on 2 May will be even higher than Real's last European home game against Bayern Munich when riot police clashed with visiting fans at half-time.
There were also violent clashes before Atletico's quarter-final home tie between police and Leicester City fans.