Athens - The Greek football federation formally apologised on Thursday to their German counterparts for the attack by a masked gang during a Youth League match between Olympiakos and Bayern Munich.
"On behalf of the executive committee of the Hellenic Football Federation and myself, I wish to express the deepest adherence and sincere apology of the whole Greek football family as regards the unacceptable and odious incident that took place during the Youth League match," wrote the letter by Greek federation president Evangelos Grammenos.
Grammenos assured the German federation that his federation "absolutely condemns in the most definitive way any violent conduct in football venues as such conducts blatantly offend fair play and the noble values of our beloved sport.
"Please pass on to the family of Bayern Munich and the victims of this cowardly attack our heartfelt apology and sympathy," the letter concluded.
Bayern Munich complained to UEFA after some fans needed hospital treatment following the attack on Tuesday in the Under-19 match won by the Germans 4-0.
According to Bayern, three German supporters needed treatment for their injuries, but were later "fortunately able to leave the hospital."
Greek police said a large group of people, wearing masks or helmets, invaded the venue where the match was being held and started attacking Bayern fans.
They announced that one arrest of a 31-year-old Olympiakos supporter has so far been made and another five have been identified and are being sought.
Police searched the home of the man arrested and found a pistol, cartridges, fire crackers, flares, knuckle-dusters, face masks and other objects which were seized.
They also searched two fans' clubhouses where they confiscated wooden rails, metal bars, knives, face masks, flares and gas masks.
Meanwhile, Sports Undersecretary Lefteris Avgerakis said the government will close down supporters' clubs which do not comply with the current legislation.
He said there are only 10 certified legal clubhouses while there are dozens, including top flight teams, which do not have licenses to operate.