Celtic Football Club has said any fans convicted over trouble on board a plane which caused an emergency landing will be banned from future international travel and the club's ground.
The club spoke out after reports of a major disturbance on board a charter plane returning 148 Celtic fans to Glasgow, which forced an emergency landing at Cardiff International Airport.
The Boeing 737, en route from Santiago in northern Spain to Glasgow, was carrying supporters home after their team's Uefa Cup game against Celta Vigo.
Celtic chief executive Ian McLeod said any fan found guilty of charges would not be allowed to sully the good reputation of the club.
In a "full emergency" situation, South Wales Police boarded the plane - now on the runway at Cardiff - to take statements from crew members and passengers.
Several passengers were removed from the plane for further questioning.
Police said six males from Glasgow were arrested - two 37-year-olds, and others aged 40, 42, 45 and 51.
'Unruly' passengers
They were arrested on suspicion of violent disorder and taken to Barry police station.
The remaining fans were due to be sent back to Glasgow on a bus.
The Royal Air Force scrambled two helicopters as a precaution before the plane's crew elected to divert.
When the plane landed, nine fire engines and ambulances joined police at the scene.
Ian Macauley of airline Astreus told BBC News 24: "It became apparent during the flight that a number of passengers were becoming unruly.
Helicopter scrambled
"We understand somebody may have been smoking on the aircraft, which is completely forbidden.
"When the passengers' ways were pointed out, a number of people got involved in something which became a fracas."
It is not known whether alcohol played a part in the incident, which one member of crew described as a "riot" at one point.
Mr McLeod said anyone found guilty of any charge would be banned from following the club.
He said: "Their action has led to their subsequent arrest and should this be proved and lead to conviction, these individuals will have clearly undermined the reputation of the Celtic support.
'Not too bad'
"Such action will not be tolerated by Celtic and if convicted these individuals will not only be banned from any future international travel but will be banned from Celtic Park."
According to passenger Steve Prince, the situation was not so bad as to deserve the term "riot".
The problem began when the pilot told passengers they would be detained on the runway at Glasgow, he said.
"After that, there was a discussion between one of the passengers and the cabin crew - it was a little bit heated but not too bad," he said.
"One of the passengers leaned over and tapped one of the cabin crew on the shoulder.
"The next thing, we were descending at a rapid rate and heading to Cardiff.
"I'm a little surprised to hear there had been a riot on board. There were not any fierce postures taken."
He claimed "no alcohol whatsoever" had been sold or consumed on the plane.
http://news.bbc.co.uk/1/hi/wales/2573741.stm