Police have said they are investigating a GAA match in County Tyrone on Sunday to see whether Covid-19 regulations were breached.
Dungannon Clarkes won their first Tyrone Football title in 64 years as they defeated holders Trillick 8-7 in a dramatic penalty shootout in Omagh.
Crowds came onto the pitch, leading to concerns about social distancing.
First Minister Arlene Foster said she is "deeply concerned" after seeing images from the match.
PSNI Ch Supt Ryan Henderson said: "We are aware of an incident at a GAA match in Omagh yesterday and will be reviewing all available evidence to determine any potential breach of the Health Protection (Coronavirus Restrictions) Regulations NI 2020 or breach of any other statute identified in respect of any individual."
In a statement Ulster GAA said that while it was a moment of "great joy", the on-pitch celebrations breached GAA protocols and public health guidelines.
"The dramatic nature of the conclusion of the game probably added to the exuberance, but we are living in a pandemic and the post-match scenes did not portray the association in a positive light," the statement added.
Jubilant spectators flooded on to the pitch after the team won the Tyrone Senior Football Championship.
Deeply concerned about the images from yesterday’s GAA match. Significant milestone for Dgn but Covid-19 is no respecter of victories. Other events being responsible. Sport & health will be the losers. @UlsterGAA need to address this. Serious questions arising from videos.— Arlene Foster #We’llMeetAgain (@DUPleader) September 21, 2020
Mrs Foster said that despite the fact that the win was a "significant milestone for Dungannon, Covid-19 is no respecter of victories".
She said "other events" were being "responsible" and "sport and health will be the losers".
The GAA said protocols surrounding all aspects of the playing of games have been introduced and "for the greater part, they have been universally observed".
"The GAA has acted in a positive manner since the outbreak of the pandemic, with attendances at games strictly regulated," it said in a statement to the BBC.
"Our supporters have responded positively and responsibly, but last night's scenes undoubtedly placed GAA members and their local community at greater risk to Covid-19."
The association called on people to behave responsibly.
"The scenes of last night cannot be repeated or we will risk going back to a position where all games will be played behind closed doors," it said.
Im proud to be a member of the GAA. Our Association has led by example throughout this pandemic. Our clubs and County Boards were the vanguard of the community response to Covid19. We will not allow our games to be demonised and scapegoated by anyone— Sinéad Ennis (@EnnisSinead) September 21, 2020
Sinn Féin MLA for South Down Sinéad Ennis said the GAA had "led by example throughout this pandemic".
"Our clubs and County Boards were the vanguard of the community response to Covid-19.
"We will not allow our games to be demonised and scapegoated by anyone," she said on Twitter.
A spokesman for the Department for Communities said that at the beginning of August the Executive announced that some spectators can attend organised outdoor sports fixtures or events.
"The department issued guidance to assist sports governing bodies, clubs and venue operators comply with the regulations, which provided guiding principles surrounding the safe return of limited spectators at outdoor sports events," he said.
"It included details on how spectators should follow the guidance and highlighted the required behaviour of spectators attending the events to help reduce the possible spread of Covid."
In July, the GAA said up to 400 people, including essential match personnel, will be allowed to attend some GAA matches in Northern Ireland.