Spanish police have seized over 11 tonnes of knock-off football team shirts in a crackdown on counterfeiting ahead of this weekend's Champions League final and the upcoming Euro 2024, they said Friday.

Officers found the jerseys of different Spanish football clubs and European national teams, along with counterfeit luxury watches, leather goods and electronic equipment, during searches of 15 heavy-duty trucks, police said in a statement.

"The counterfeits were destined for various organisations based in Spain, which intended to distribute them through street sales, social networks and websites," the statement said.

Police said they seized over 46,000 counterfeit items -- including over 36,500 jerseys -- with a street value of more than six million euros ($6.5 million).

The operation, which is ongoing, began in April after Spain intercepted two tonnes of counterfeit football jerseys from China.

This led to the discovery that "a large shipment of counterfeit goods" was arriving in Spain "to be supplied to criminal organisations that intended to place counterfeit sports kits on the illicit market on the occasion of the Champions League final and Euro 2024."

Real Madrid will seek to win Europe's biggest club prize for a record 15th time when they take on Borussia Dortmund in the Champions League final on Saturday at Wembley Stadium in London.

Germany will host the 2024 European Championship finals from June 14 to July 14.

Counterfeits are a global phenomenon, whether for fashion, toys, electronics, food or pharmaceuticals, estimated by the Organisation for Economic Cooperation and Development (OECD) to represent 2.5 percent of world trade.