The Hellenic Police raided several soccer fan clubs in Athens on Friday, following similar operations in Thessaloniki on Thursday.
The operations are part of an investigation into the murder of 19-year-old Alkis Kampanos this week in Thessaloniki from hooligans.
According to police sources, the raids started in the PAOK club on Halkokondyli Street, near Omonoia, in central Athens and continues in the fan clubs of other teams.
Dozens of officers from various police services are taking place in the operations, the same source said, adding that no detentions have yet been made.
Kampanos was attacked along with two friends by a group of at least 10 individuals with knives and rods late Monday night. A 23-year-old known to police authorities was arrested and charged Thursday with one count of homicide and two of attempted murder. He was given until Monday to prepare his defense.