There has been an attack on the Catholic church in the Harryville area of Ballymena.
The church has been attacked in the past
Two paint bombs struck the front door of the Church of Our Lady, where Mass-goers endured weekly loyalist pickets between 1996 and 1998.
SDLP councillor Declan O'Loan said it would set back efforts to repair divisions in the town.
A loyalist community group from the area has said it will help clean up the paint.
Geoff Calderwood, chairman of Harryville Ulster Scots Society, was at the church on Tuesday morning to view the damage.
"We are working to make Harryville a better place and we do not want this sort of thing," he said.
However, he said his group had made inquiries in the area and "nobody knows anything about the attack".
He said he believed dissident republican supporters may have been responsible in an attempt to have the blame put on loyalists.
Mr O'Loan said there had been several attacks on the church through the years.
"But it has been largely undisturbed for some time. So it is very regrettable to hear of this further attack."
Sinn Fein's North Antrim assembly member Philip McGuigan called the attack "disgusting".
"In the past we have seen petrol bombs, graffiti and windows smashed.
"It truly sickens me that people would go out and do this sort of damage purely to fuel their hatred for Catholics," he said.
Last year, members of Protestant church congregations in Ballymena helped to clean paint off the walls of the Church of Our Lady after attacks.
In April of this year, a loyalist mural near the church was removed.