Spain - Madrid will deploy an unprecedented number of police and security personnel for Saturday's all-English Champions League final, and use a drone for the first time to monitor fan activity.
With Spain's terror alert set at its second-highest level, Spanish authorities have also banned trucks weighing over 3.5 tonnes from driving near the Wanda Metropolitano stadium which will host the match between Liverpool and Tottenham deemed "high risk".
Trucks will also be barred from the vicinity of the two fan zones that will be set up in the city centre.
"We will have a very, very robust security apparatus in place to try to ensure everything takes place normally and everyone can enjoy (the match)," the director general of Spain's National Police, Francisco Pardo, told a news conference Thursday to outline the security measures for the game.
Some 4,700 police officers and private security guards will be deployed for the match, more than the nearly 4,000 used for last year's Copa Libertadores final between Argentine rivals River Plate and Boca Juniors in Madrid, a match that was also declared "high risk" by authorities.
"This will probably be the biggest deployment to guarantee security which we will carry out at a sporting event" in Madrid, said Pardo.
Police will for the first time deploy a drone to provide aerial monitoring to prevent fan trouble at a sporting event, which will work in coordination with police helicopters, he added.
'Dealt with robustly'
The authorities expect around 32,000 ticket-holding fans from both teams will attend the match at the 68,000-capacity stadium, and thousands more to come to Madrid without a ticket from Britain as well as southern Spain and neighbouring Portugal, which have large English expat communities.
British police are sharing intelligence with their Spanish counterparts and will be in Madrid to assist in the security operation.
"Fans who choose to get involved in disorder should be warned that they can expect to be arrested and dealt with robustly by the Spanish police," said the head of the London Metropolitan Police operation at the final, superintendent Nick Collins.
While there is no great history of rivalry between the two sides, six Liverpool supporters were arrested in Barcelona for public disorder on the eve of their meeting in the Champions League semi-final first leg.
Videos posted to social media showed a Liverpool supporter lifting a man selling beers into the water of a fountain in the city centre as surrounding fans laughed and cheered.
English fans were involved in a number of altercations, and even threw bottles and other objects at police.
Spanish sports daily Marca summed up the angst which the Champions League final is sparking with a front page headline on Monday that read in big yellow letters: "FEAR".
'Avoid many conflicts'
The authorities plan to keep the fans of each team separate at all times. They will arrive at different airport terminals and take different metro lines to the stadium from their respective fan zones.
The Tottenham fan zone will be set up at Colon Square, some 2.5 kilometres (1.5 miles) from the Liverpool fan zone at the Felipe II Square.
Past experience has shown that by keeping fans separate "the atmosphere is more relaxed, more festive and we avoid many conflicts," said the representative of Spain's central government in the region of Madrid, Maria Paz Garcia-Vera.
Ticketholders will have to pass through several rings of security before reaching their seats for the final.
Bar and restaurants near the fan zones have expressed fears about possible fan trouble, with several managers telling Spanish media they plan to close their doors on the day of the final or hire extra private security.
"We will see what scenario is like that day" before deciding if we close, a waiter at a tapas bar near Colon Square, who asked not to be identified, told AFP.