The graves of nearly 40 people have been desecrated in an overnight attack on the republican plot at Milltown Cemetery in west Belfast.
Paint was thrown over the headstones, including those of hunger striker Kieran Doherty and three IRA Volunteers killed by the SAS in Gibraltar.
The main memorial defaced contained a copy of the 1916 proclamation of Irish independence and it will need special treatment to return it to its original condition.
It is the fourth attack on the plot in the last six years.
In 2004, there was a series of attacks on the graves of republicans, including that of hunger striker Bobby Sands.
Padraic McCotter, chairman of the Belfast National Graves Association said three or four republicans were buried in each of the 12 plots.
“Sixty-six British soldiers are buried in Milltown and not one of their graves is touched. That is the way it should be. The Republican graves should be treated in just the same way.”
Mr McCotter said the yellow paint which had been poured over the 1916 Irish Proclamation of Independence on the central monument at the plot was proving difficult to move.
He said that certain graves had been deliberately untouched.
Mr McCotter said he would not speculate as to who may be behind the attack.
“It is just wrong. Who knows what the twisted logic of these people is.
“We have been here since 9am this morning cleaning the graves up, and we have professional people here to help. But it’s still hard for the families to see this happening again.”