The DUP will table a motion of no confidence in the Sinn Fein mayor of Causeway Coast & Glens Council after he eulogised an IRA killer.
Councillor Aarron Callan, the DUP group leader on the council, has called for Sean Bateson to resign and said he's not able to represent the people of the borough following his comments.
The issue will be debated at the next meeting of the council.
In a post on Twitter, Sean Bateson praised convicted murderer and hunger striker Thomas McElwee on the 38th anniversary of his death.
"Oh gallant South Derry you are forever blessed. In the struggle for freedom you have given your best. There's Hughes and there's Bateson, Sheridan and Lee and inscribed with their names now brave Tom McElwee," the Sinn Fein councillor tweeted.
"Thomas McElwee who Cllr Bateson was eulogising was convicted and sentenced for the murder (later reduced to manslaughter) of an innocent woman in her clothes shop in Ballymena. It is Yvonne Dunlop who we should remember, not someone who deliberately went out to destroy her property and take her life," said Councillor Callan.
"Sean Bateson, like myself, was not alive during the hunger strikes or when the troubles were blighting Northern Ireland. Unfortunately he is only joining more senior Sinn Fein representatives who address parades, or dance in the street to celebrate IRA terrorists despite full knowledge of the impact their words and actions have on those who suffered at the hands of the Provisional IRA."
A Sinn Fein spokesperson said: "Sean Bateson will not be standing down. The hunger strikers are held in the highest of esteem across Ireland and internationally because of their bravery and sacrifice. The Good Friday Agreement enshrines the right of everyone to commemorate their dead and republicans will continue to remember all the hunger strikers with dignity and respect."
Councillor Callan said there is now an opportunity to retract the comments.
"There is the opportunity for Cllr Bateson to recognise the mistake he has made [...] and act in a way that respects the office of Mayor and the citizens of our Borough. If he does not then we believe the only option is for Councillors to decide whether or not he commands the confidence of the Council," Mr Callan said.
On Thursday, Ulster Unionist leader Robin Swann also called on Sean Bateson to resign.
Mr Swann said that the post was "another example of Sinn Fein mocking and disrespecting innocent victims".
"He has proved he cannot be a mayor for all the citizens of Causeway Coast and Glens and should step down before he causes any more offence," the North Antrim MLA said.
In response to the criticism, Mr Bateson said that he would "continue to attend republican commemorations which honour and remember those men and women who I believe died in the cause for Irish freedom".
"They are held with the utmost dignity and respect," he said.
The 26-year-old mayor said that the right to remember one's dead is protected under the Good Friday Agreement.
Mr Bateson pointed out that he was a history teacher and was "fully aware of the different perspectives with regards to our past".
"There never will be a 'one size fits all' narrative of our conflict, which is hundreds of years of complexities," he said.
"It is exactly this understanding which allows me to respect those that hold a unionist and British interpretation."
Mr Swann said that McElwee was "many things, but brave was not one of them".
McElwee was convicted of being part of an IRA gang who planted bombs in Ballymena in October 1976. One killed 26-year-old shop owner Yvonne Dunlop. He was sentenced to 20 years, and joined the 1981 hunger strike, dying after a 62-day fast.
"We must never forget Thomas McElwee got to choose the timing and manner of his death. Yvonne Dunlop, like the rest of the IRA's victims, was given no choice," the UUP leader said.
In May Mr Bateson was criticised for posing for photos at memorials to two dead IRA men. A Twitter post boasting about tearing down a Union flag - described as the "butcher's apron" by Mr Bateson in the tweet - also surfaced.