Gardaí in Co Kerry are investigating damage costing €100,000 caused to a controversial mobile phone mast near Fenit which had been about to go into operation.
Damage was caused at the Meteor mast's communications cabin at Ballygarron, The Spa, on the night of November 30th/December 1st.
Gardaí said the cabin door was forced open and communications equipment set on fire.
The Meteor mast was recently granted planning permission after the telecommunications company appealed a county council refusal to An Bord Pleanála.
There had been widespread opposition to the mast, located between Tralee and Fenit. Overlooking the coastline, it is seen from a wide area.
Sinn Féin TD Mr Martin Ferris was the chairman of an anti-mast action committee, AMAC. The committee disbanded after An Bord Pleanála granted permission to Meteor Mobile Communications Ltd early in September.
Mr Ferris said no one in the locality would condone anyone taking the law into their own hands. "But there would be an understanding why it happened," he said. There are up to 50 houses within a kilometre of the mast, Mr Ferris said.
The committee had considered taking a case to the High Court but decided against it because of the costs involved, he said.
Kerry County Council had refused permission on the grounds that it contravened the county development plan as it is within one kilometre of residential properties.
An inspector from An Bord Pleanála also recommended refusal on the grounds that it "would be visually obtrusive and would have significant impact on the visual amenities of the area".
An Bord Pleanála granted permission, referring to the national strategy regarding the improvement of mobile communications, and said the site was not restricted in the county plan.