The German government has been warned that drones are the biggest terrorist threat to the upcoming European Championship.
This summer, Germany will host its first major tournament since the 2006 FIFA World Cup. Euro 2024 will be held in 10 different venues from June 14 to July 14.
The country may impose a national ban on drones over fears they could be used in terrorist attacks.
"Drones are becoming one of the biggest problems," Andreas Roskopf, head of Germany's federal police union (FPG), told German newspaper BILD.
"Before, during and shortly after the European Championships, a comprehensive, nationwide ban on drone flights should be implemented throughout Germany," Roskopf added.
Unmanned aerial vehicles have become a key element of modern warfare and have been regularly used in the conflict between Russia and Ukraine.
In the past two months, Houthi forces in Yemen have relied on unmanned missiles to attack Western merchant ships in the Red Sea and Gulf of Aden, and Islamic State (IS) has also carried out terrorist attacks using drones.
Terrorism and drone expert Nicolas Stockhammer, a professor of international studies at the Danube University in Krems, Austria, echoed Roskopf's concerns.
He warned that the proliferation of drones on the Internet is a serious concern for authorities, as is the possibility of terrorist organizations acquiring more sophisticated military drones.
"In the last 10 years, IS has repeatedly used drones for attacks - both as kamikazes and drones equipped with explosives," Stockhammer explained.
"Today, the technology is more accessible. This also increases the real risk that terrorists will resort to this cheap and remotely controlled technology. Plans for the use of unmanned aerial vehicles are readily available on the relevant forums on the Internet. The danger increases if attackers manage to capture modern military unmanned aerial vehicles such as those used in current war zones," the expert emphasized.
Meanwhile, German Interior Minister Nancy Fraser announced that temporary border controls would be in place for the duration of the tournament to tackle the growing threat posed by "extremists and hooligans".
"During the tournament we will be carrying out temporary border controls at all German borders so that we can prevent potential perpetrators of violent crimes from entering the country," Fraser said.
"This is necessary to protect this major international event in the best possible way," added the interior minister.
In December, it emerged that England supporters could be banned from drinking beer at the Euro 2024 opener in Gelsenkirchen.
The city's police chief, Peter Bott, said he was determined to crack down on drinking in the stadium and in public places, and warned he would send those misbehaving home.
"We are discussing the possibility of banning alcohol in the stadium, and I am not hiding it. We are currently also checking to what extent we can implement the ban on the use of alcohol in public places," added Bot./BGNES