Manchester United could face a points deduction after fans forced the postponement of their Premier League fixture with Liverpool.
Both the Premier League and Football Association are investigating following the mass protests around Old Trafford on Sunday.
And the organisations are speaking with Manchester United and the local authorities to piece together exactly what has happened, and where responsibility lies.
Under Premier League rules, points can be deducted where a club fails to ensure the safety of players and staff, as well as entry and exit from the ground.