A Burnley fan was stabbed in the leg and four others injured at Thursday night's Europa League defeat to Olympiakos in Athens.
More than 900 Clarets fans attended the qualifying play-off first leg at the Georgios Karaiskakis Stadium in Piraeus, which saw the visitors suffer a 3-1 defeat.
The tie was marred by off-field incidents which led to one Burnley fan needing medical attention after suffering a stab wound in the leg and also saw 22 others detained before the match before later being released without charge.
A Burnley statement on Friday morning read: “A group of 22 supporters were detained by police ahead of the game for offences relating to drunkenness, in breach of Greek legislation.
“They were detained, rather than arrested, and released later on Thursday night without charge.”
An earlier club statement had read: “Just over 900 supporters were inside the away end of the George Karaiskakis Stadium for Burnley’s Europa League tie at Olympiakos.
“The vast majority were once again impeccably behaved, with the coaching operation to transport supporters to the ground put in place by the club again a great success, as it was in the previous round in Istanbul.
“However, five of our supporters were unfortunately injured — including a person who received a stab wound to the leg — and received medical attention at the stadium.
“Those injured all travelled independently to the stadium, outside the organised travel operation.”
Burnley said they were working closely with Olympiakos and local police to investigate the incidents.
