BBCThe grounds of an historic and protected fort in the Republic of Ireland have been damaged after scrambler bikes were ridden inside its walls.
An Grianán of Aileach, a hilltop fort that dates to the 9th Century BC, is one of the most historic sites in County Donegal.
The Irish government's Office of Public Works (OPW) said it was aware of damage to the "ground surface inside the fort" and gardaí (Irish police) were investigating.
Mary McCallion, who lives close to the ancient fort, said she is "deeply concerned".
"Scrambler bikes or powerful bikes caused this damage; I would like to think that those responsible did not realise the extent of the damage.
"I cannot understand the mindset of people who would do such a thing," she said.
"Thankfully, any damage that has been caused can be repaired with the help of the OPW before the real tourism season starts."
Gardaí said the damage was caused sometime between 13:00 local time on 6 March and 14:15 on 9 March.
Jacqui Devenney also lives a stone's throw from An Grianán of Aileach.
Whoever damaged the fort's grounds, she said, didn't seem to "fully understand the historical significance of this site".
"What is so beautiful about An Grianán is that you can go up anytime and it's open and accessible.
"You could go up at a full moon and there might be 20-30 people.
"I am a photographer, and it is fantastic to see people coming here, including weddings," she said.
Designated a National Monument by the Irish government, the fort sits on a mountain top between Lough Foyle in Northern Ireland and Lough Swilly, in the Republic of Ireland.
The earliest evidence of a fort at the site dates to between 1100 and 800 BC.
The stone fort structure is thought to have been built in the 9th Century AD, and is likely to have been used by the Cenél nÉogain, a branch of the medieval O'Neill clan, for inauguration and other royal ceremonies, according to the OPW.
In the 1870s, An Grianán underwent comprehensive rebuilding works, led by Walter Bernard from the nearby city of Londonderry.
Local historian Dessie McCallion has described the damage to the ancient site as "disrespectful".
"I could not help but think the individuals who did this would not do it to their local soccer pitch, parkland, or garden," he said, adding those responsible were "thoughtless".
"An Grianán of Aileach is not a playground, certainly not the walls which can be extremely dangerous."
Sinn Féin councillor Jack Murray said he hoped those responsible for the damage would "be brought to task".
"And I would like to think this will never happen again at somewhere so special to all of us," he said.
"Thankfully the stone work wasn't damaged," Murray told BBC Radio Foyle's 20 Minutes with Mark Patterson programme.
Descriptions of those involved have been given to local police, he said.
In 2024, new opening hours were introduced at the fort following concern there had not been enough access to the historic site.
At that time, Sinn Féin TD (member of the Irish parliament) Pádraig Mac Lochlainn said there was a school of thought among historians that An Grianán of Aileach was "as important to Irish history as the Hill of Tara (the seat of the High Kings of Ireland)".
