Uefa has confirmed it will investigate the crowd trouble during Wednesday's Euro 2004 qualifier between England's group rivals Turkey and Macedonia.
Numerous missiles were thrown on to the pitch during the match in Istanbul, which Turkey won 3-2, with Macedonia players hit by coins and bottles
Midfielder Sasko Lazarevski was struck on the head and riot police had to form a shield to protect any visiting player taking a corner.
Turkey are almost certain to be charged by Uefa as a result, with any punishment possibly affecting England's visit to Istanbul in the group's pivotal fixture on 11 October.
"We are aware of incidents that have been reported from that game and await the match delegate's report which will cover all aspects of the conduct of the match both on and off the field," said Uefa communications director Mike Lee.
An investigation has been opened on the basis of information already received
Uefa spokesman Mike Lee
"We have already received the referee's report and reference has been made to missiles coming on to the pitch.
"The final decision on opening a disciplinary procedure will only be taken once we have received the official delegate's report and reviewed video evidence.
"However an investigation has been opened on the basis of information already received."
The crowd trouble raises questions about the security of England's players for what is likely to be the deciding fixture in the group in October.
Turkish fans also lit flares in the stands when their team twice fought back from a goal down to snatch victory.