Serious crowd trouble has marred the big Irish Premier League clash between Glentoran and Linfield at the Oval.
Fans threw missiles at each other after the match
Rival fans threw missiles at each other and fought on the pitch after Glentoran won 3-2 thanks to a late goal from former Linfield star Chris Morgan.
It was some time before riot police came on to the pitch to restore order.
Irish FA chief executive Howard Wells said he would be asking what pre-match preparations had been made considering a large crowd was expected.
"I shall want a report on it. We are trying to attract more people into games but they are not going to come if they see this kind of thing going on," said Wells.
"It is just unacceptable to all people. It is frightening for those who were at the game, for families and children, and it means football is not a winner.
"Everybody has got to get together and take responsibility and recognise we are all responsible for the way we present football.
"Frankly we have fallen down on it big time today in a number of quarters."
The Irish FA inquiry will demand answers about why security arrangements were found so badly wanting.
Spectators at the Linfield end of the east Belfast ground were able to get through a gate to gain access to the pitch.
Stones and bottles were thrown from the pitch into the main stand where Glentoran fans were accommodated.