Emergency search-and-rescue operations off Co Donegal could be hampered in coming weeks after damage estimated at £50,000 was caused to Carrickfin airport on Sunday night.
Gardai are investigating the incident after most of the runway and approach lights were smashed and perimeter fencing cut.
Airport management said it could take six to eight weeks to repair all the damage, and in the meantime night operations would not be possible. The scheduled daytime service to Dublin would also be affected during periods of bad weather and low visibility.
A spokesman for the Air Corps said its emergency helicopter, based at Finner Army Camp in south Donegal, used the airport as a secondary landing facility. While search-and-rescue operations would not therefore be immediately affected, they could be in certain circumstances, he said.
Air ambulance services would be hit, the spokesman said, as the airport was used for emergency evacuations from the islands, and for airlifting people off ships. It was also used for training purposes and refuelling.
A spokesman for the Irish Marine Emergency Service said the loss of any facility was a matter of concern. "The people who carry out damage like this should stop and think of the people at sea and of the emergency crews. The Air Corps helicopter crews work in very difficult situations and in terms of marine rescue any facility is important to us," he said.
The operations manager at the airport, Mr Brendan Boyle, estimated the damage at nearly £50,000. Lights had been broken along a mile-long stretch of runway. "The entire operation of the airport is now at risk because of this attack," he said.
There has been much controversy at the airport recently over plans by a Swedish-owned company to build an aircraft repainting plant. A local conservation group strongly opposed the plan, saying it feared it would cause pollution and be an imposition on the coastal site.
An Taisce also lodged an objection, but just a week ago An Bord Pleanala granted planning permission, upholding a decision by Donegal County Council but applying certain conditions.
In a statement last night the conservation group involved in the planning appeal against the painting plant condemned the attack on the airport and described it as "a deplorable act".
Gardai, appealing for information, said there was no evidence to link the attack with any group or individual. They said they were keeping an open mind about a possible motive.