The owners of land on Benbulben in Co Sligo have been ordered to remove a giant 'No' sign.
The 100 foot sign made out of plastic sheeting was placed on the North facing side of the mountain from around 4 am this morning.
Those responsible say they have 'full permission' from the landowners.
The move has drawn criticism, with some saying the mountain had been defaced.
Sad to see the tourist attraction of #Benbulben defaced this am, neither side has freedom or need to undertake such 'cultural vandalism', I'm sure @sligococo will deal! pic.twitter.com/3B0uoE4XXi
— Damien McCallig (@DamienMcC_dli) May 17, 2018
Sligo County Council said the land where the lettering was placed is "commonage", and therefore the council "has no role in this matter".
Tommy Banks, a member of the Sligo for Life No Campaign, is one of the organisers.
He told Ocean FM: "There's several teenage young men here helping out - men of all ages - and women as well down getting ready tea and sandwiches.
"It's a cry from the mountain to save Ireland's babies, because no-one is listening."
But in a statement, the National Parks and Wildlife Service said: "The insinuation of alien materials such as this onto a special area of conservation is insensitive to its conservation status and incompatible with the habitat.
"The owners should procure its immediate removal so that Ben Bulben is returned undamaged to its natural and beloved state."
