Uefa is investigating the crush involving Manchester United fans at the Champions League tie against Lille.
United supporters appeared to be pressed against crash barriers in an overcrowded section of the ground and at least two people had to be lifted over the barriers to safety.
Riot police then fired tear gas and at those who were trying to climb over the fence to escape the overcrowding.
UEFA said that it was investigating possible violations of binding UEFA safety and security instructions by the host club, as well as the alleged improper conduct of both sets of supporters. The matter will be discussed at the next ordinary meeting of the UEFA Control and Disciplinary Body on 22 March.
United goalkeeper Edwin Van der Sar suffered double vision as a result of the tear gas fired into the stand.
Television reports suggested the gates at the back of the stand had been opened by police to allow United supporters with tickets for the home section of the stadium to sit with their fellow supporters.
“We have obviously received a lot of information from various sources but we would welcome any more detail from fans in the affected area,” said United director of communications Phil Townsend.
United had expressed concerns about the basic facilities at the ground before the match.
Uefa spokesman Rob Faulkner said: “Having seen what went on on the security side and in the match itself, it would be standard procedure for the referee to report the incidents and for the Control and Disciplinary Committee to take the appropriate action.
“The whole issue of Lille playing in that stadium will also need to be addressed.
“We cannot say now what action the Disciplinary Committee will take, but if they find against Lille, it could well be severe.”
Uefa’s match delegates were so concerned that there were appeals over the loudspeakers for calm in the away end.
“We will be submitting a report to Uefa,” said a United spokesman. “We met with Uefa officials, FA officials and the police straight after the game. We want to hear the accounts of supporters who may have been involved and we will submit that to Uefa.”
Meanwhile, UK sports minister Richard Caborn has demanded Uefa ensure grounds used for the Champions League meet minimum safety requirements.
“I think some of the grounds are not coming up to what even Uefa are saying are the minimum standards,” he said.
“I think one’s got to be asking Uefa are they now going to be taking action with those grounds that are not coming up to the standards?
“Not a few hours before the match but weeks before the match so they go out, they look at those grounds and indeed if they’re not up to standard then Uefa – by their own code – ought to be taking action.”