European football’s governing body (UEFA) has opened disciplinary proceedings against Arsenal and FC Cologne following incidents during their Europa League encounter at the Emirates Stadium in North London on Thursday.

The match was delayed by an hour as an estimated 20,000 away fans arrived at the venue without tickets and prevented arsenal supporters from getting to the turnstiles.

The German club face four charges, including crowd disturbances and setting off fireworks while the Gunners face a charge over blocked stairways.

UEFA said its disciplinary committee would deal with the case next Thursday, with its rules stating that the host club is “responsible for order and security both inside and around the stadium before, during and after matches.”

The rules also say the hosts are “liable for incidents of any kind… Unless they can prove that they have not been negligent in any way in the organisation of the match.”

The regulations however state that each club can be punished for “inappropriate behaviour on the part of their supporters.”

Cologne supporters – whose side were competing in European competition for the first time in 25 years – were allocated 3,000 tickets for the match but another 17,000 fans are believed to have made their way to the ground.

Congestion and outside the ground led to kick-off being delayed by one hour until 9:05pm, with Arsene Wenger’s side eventually winning 3-1.

Arsenal have already begun an investigation into the incidents, which led to five people being arrested following crowd disturbances.