A dispute between councillors in Mid and East Antrim spiralled into name-calling on social media after a Sinn Fein member admitted he branded a unionist a "d***head" in the chamber.
Councillor James McKeown aimed the slur at TUV deputy mayor Timothy Gaston in Ballymena during a fraught debate on Monday night.
The Larne Times reported that the insult was made during exchanges about links from the council's website to external organisations such as the Reserve Forces and Cadets' Association.
The council's veterans' champion John Carson of the DUP had asked fellow councillors to allow the link. But when Sinn Fein said the matter should be deferred, he replied he was "not surprised at Sinn Fein/IRA".
Mr McKeown said that, as far as he was aware, there were no IRA members in the chamber.
"We are members of Sinn Fein, a political party," he added.
After Mr Gaston backed Mr Carson's bid to allow the websites to be linked, the TUV member said: "As councillor McKeown has said, they are maybe not in the IRA, but that doesn't say they are not controlled by the IRA."
Mr Gaston later added that he wished to raise a point of order over the use of "very unsavoury language used by one of our councillors".
"I want to throw the floor open to councillor McKeown to see if he wants to repeat what he said when he muttered below his breath," he said.
The Sinn Fein member denied "muttering" the remark, but later on social media he was challenged again by Mr Gaston.
Mr Gaston wrote on Facebook: "There you have it folks, the terrorist sympathiser that is Carnlough Jimmy is only man enough to call me a 'd***head' off microphone."
Mr McKeown admitted to his local newspaper he had called Mr Gaston a "d***head", but was "not ashamed". He said the remarks were made out of frustration after claims the Sinn Fein councillors were linked to the IRA.
"I am 150% certain that there are three members of Sinn Fein and no members of the IRA in that chamber, and those three members have a mandate," he added.