The husband of a woman killed in the 1998 Omagh bombing has said families of other victims of the atrocity approved his move to attach a plaque to the memorial in the Co Tyrone town.
Over the Christmas period Kevin Skelton attached a plaque to a memorial at the location where the devastating car bomb exploded in the Real IRA attack.
It reads: "In memory of the 29 men, women, children and unborn twins who were brutally murdered and over 300 people injured by a dissident republican terrorist car bomb on the 15th August 1998. Never forgotten."
Reference is made to "dissident republican terrorists" at the nearby memorial garden but there was nothing placed on the Market Street site.
Kevin Skelton's wife Philomena was killed in the bombing. He said he placed the plaque on the memorial because he "wanted the truth to be told" and there was no indication of who carried out the attack.
He said he didn't do it behind anyone's back but in broad daylight.
"I don't think I have done anything wrong," he told the BBC.
"The people who claimed it are the people who are named on the plaque. It is not offensive to anyone.
"In another 50 years people will come along and at least know what happened. It is a reminder of the history of Omagh."
Mr Skelton said he had a "very good response" and not had one person saying he had done anything wrong.
"I didn't expect to get what I go. I did meet with families and people injured. I am chairman of Families Moving On. We are a large group and they all back me."
Fermanagh and Omagh District Council said the placing of the plaque was not authorised. The matter is to be raised at Tuesday night's council meeting.
Mr Skelton said there was nothing to be gained from removing the plaque.
"We held a service on the 15th of August here [at Market Street] for the first time in 20 years. I always said after 20 years anything to do with the Omagh bomb I was moving away from it and this was to cap it off. This is me and the Omagh bomb finished.
"Now is the time to move forward and work for the people left behind who need our help."