Questions have been raised this morning (Saturday) after the Tricolour was erected in Enniskillen overnight.
The Republic of Ireland's flag was first spotted early this morning.
It is understood it has since been removed.
When contacted by this newspaper, a PSNI spokesperson said they had not received any reports about the erection of a flag.
Enniskillen Councillor Keith Elliott said: " I am very angry to learn that last night someone managed to force their way into the grounds of Enniskillen Castle to erect a Tricolour on the flagpole.
"This is an action with the single intent of stoking up tensions in the area.
"I have been speaking to the departmental officials responsible for the castle buildings and the flagpole and it is has since been removed."
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