Police are treating the daubing of IRA graffiti close to Troubles memorial in Enniskillen as a "hate crime".
The letters 'IRA' were painted on a wall of the Clinton Centre in the Belmore Street area of the town over the weekend.
The centre is located near to a memorial to victims of the 1987 IRA bombing when 11 people died as they gathered for a remembrance event.
A 12th victim later died, while dozens of people were injured.
A PSNI spokesperson said: "A report was received on Sunday evening, November 26, that graffiti had been sprayed on a wall.
"Enquiries into the incident, which is being treated as a hate crime, are ongoing.
"Anyone who may have witnessed any suspicious activity in the area, or who has any information which could assist, is asked to contact police on 101."
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Kenny Donaldson, director of victims' group the South East Fermanagh Foundation, called it a "deplorable action".
DUP MLA Deborah Erskine said it was a "despicable act".
"This graffiti is very close to the memorial that Enniskillen bomb families placed in remembrance of their loved ones," she said.
"A few short weeks ago I joined with those families in a dignified remembrance event on November 8.
"The respect of those families is in sharp contrast to those that carried out this disgusting graffiti incident, in such a public way."
