Seven supporters of Austrian soccer club Rapid Vienna were arrested in Thessaloniki on Thursday night before their team?s Europa League playoff match against local side PAOK.
The Thessaloniki team won 2-1 but the victory was soured by clashes between rival fans ahead of the kickoff.
Five of the suspects are Austrian, one Polish and one Croatian.
They were arrested after flares were fired at PAOK supporters.
The return leg is in Austria on Thursday.
In the other game involving a Greek time, Atromitos held Newcastle to a 1-1 draw in Athens.