The Football Association are to investigate the unsavoury scenes at the end of Saturday's clash between Nottingham Forest and Derby at the City Ground.
After helping Forest record a 3-2 victory in the Coca-Cola Championship clash, striker Nathan Tyson picked up a corner flag and waved it in celebration in front of the Derby fans in the Bridgford End. Rams players Dean Leacock and Gary Teale confronted Tyson, prompting the majority of the other players to rush over and get involved as stewards fought to keep supporters off the pitch.
An FA spokesman said: "The FA can confirm that we will be investigating the incidents at Nottingham Forest as a matter of urgency."
Forest went 3-0 up through Radoslaw Majewski, Dexter Blackstock and Tyson before Derby fought back in the second half.
A Wes Morgan own goal and a Jake Livermore effort brought them back into the match, but the hosts held on to claim their first success over their local rivals since March 2003.
Forest boss Billy Davies said: "I didn't see the incident but if that's what Nathan has done then I will look at the video.
"I remember the last time Derby were here and Robbie Savage was waving a Derby scarf around.
"There was very little made of that and we hope it will be the same for this."
Derby manager Nigel Clough also missed the incident involving Tyson.
He said: "I was in the dressing room, which I personally think all managers and benches should be at the final whistle."
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