Arsenal have sent a report to UEFA to find out why supporters missed out on the kick-off against Napoli in December.
Hundreds of Gunners fans missed the beginning of the Champions League clash at the Stadio San Paolo despite the north London club having an agreement with Italian authorities to avoid any problems in Naples.
A letter sent to Arsenal supporters who travelled to Italy read: "Our supporters' safety is of paramount importance to the club and we did everything possible to ensure supporters were escorted safely and on time to the stadium by the Italian authorities. This had been planned and agreed in advance, but did not happen on the night.
"Reports of the events have been made by Arsenal Football Club, the Football Association and the British Consulate, and have been sent to UEFA.
"We now await UEFA's response to the reports and the club will be making every effort to ensure there is not a repeat in the future.
"In addition, the club will be making contact with our counterparts at Swansea City FC, in order to share our experience before their Europa League tie in Naples.
"Once again we are sorry about what happened to our supporters in Naples and thank you for your continued support."
