The damage was discovered by the caretaker at the Church of Our Lady at Harryville in Ballymena on Tuesday morning.

Arsonists had piled up pews and carpet inside the church and set fire to them.

The attackers removed a heavy metal grill and smashed reinforced glass to get into the church.

The Catholic Bishop of Down and Connor, Patrick Walsh, visited the church on Tuesday morning to see the damage.

He said all such arson attacks were to be deplored.

"I know all right-minded people will have great sympathy for the priests and the people of the parish who, in the face of all they have suffered, have been amongst the foremost in working to promote good community relationships in Ballymena."

Local councillor Declan O'Loan said there was no doubt the attack was sectarian but insisted this did not represent the mainstream view in Ballymena.

"While there are always small groups of people prepared to do the type of thing that happened last night, we should not fall into the trap that it represents some mainstream view.

"I'm quite convinced it does not."

Picket mounted

Loyalist protesters mounted a weekly picket outside the County Antrim church during Saturday evening Mass between September 1996 and May 1998.

The protests were called off shortly after the Good Friday Agreement received 71% support in a referendum.

The picket was mounted because of loyalist anger over nationalist objections to a march by the Protestant Orange Order through nearby Dunloy.

The attack is the latest in a series on Catholic churches and comes in the wake of recent unrest over the controversial Drumcree marching dispute.