A suspected Islamic State supporter arrested last week had applied for an accreditation to work as a steward at Euro 2024, a German state minister said on Monday.
Herbert Reul, Interior Minister of North Rhine-Westphalia, said there were "no concrete attack plans.
"We have checked all those who will be working in these areas of security and order because they need accreditation," he said.
"And during the accreditation process, it became apparent that this young man could pose a problem and that is why we are now taking careful care of him."
The man with German-Morrocan-Polish citizenship was detained on Friday at Cologne/Bonn airport. He is suspected to have transferred $1,700 via a crypto currency exchange to an account of the Khorasan Province branch of jihadist group Islamic State.
The suspect is accused of supporting a terrorist group and violations of Germany's foreign trade and payment law.
Sources told dpa the man had sought accreditation for side events at the Euros, outside the stadiums, such as at public viewing areas.
German Interior Minister Nancy Faeser named the arrest "a big success" for the local authorities.
"It's good that the security forces have taken notice, which shows that our concepts for security checks are obviously working,’ she said.
Faser and Reul were speaking in Neuss at the official opening of the International Police Cooperation Center (IPCC) for the month-long Euros which kick off on Friday.
"We have a very high risk in abstract terms, but we have nothing concrete," Faeser said, adding that there can never be 100% certainty.
"Security is the highest priority for us. We are very, very well prepared and I therefore hope that it will be peaceful and safe games."
