Greek police on Wednesday arrested 97 people for possessing or selling forged tickets. Many others - mostly British - attempted force their way past the security perimeters around the Olympic Stadium hours before kick-off.
"We have launched an inquiry, but following our discussions with the Greek police and the organising committee, it seems as though Liverpool fans were mainly to blame," UEFA's director of communications William Gaillard confirmed.
"However, it also seems around 800 Liverpool supporters got tickets in the Milan end which we know were distributed to Milan, not any ticket agency or travel agent."
"So yes, if the club is found to have been involved in any way or hasn't acted in a proper manner, they can expect action," he said.
Gaillard said UEFA were satisfied with the actions of the local police and the organisation committee.
To be honest, it is lucky nobody was killed. The police took a decision after being attacked by fans without tickets to allow them in as it was safer and avoided any further confrontation," Gaillard said.
"Other fans knowingly bought forged tickets from touts and even from banned websites, thus putting the safety of fellow supporters, who bought their tickets legitimately, at risk."