Firefighters are currently at the scene of a gorse fire on land surrounding Knockagh Monument, a war memorial towering over the Greenisland area of south-east Antrim.
The incident was reported at approximately 3am today.
The giant stone obelisk, which stands on the Knockagh escarpment, commemorates those who perished in the First and Second World Wars, and is often surrounded by poppy wreaths and tributes laid at its base.
The fire happened the morning that a commemorative gun firing was taking place at nearby Carrickfergus harbour, marking the Duke of Edinburgh’s 97th birthday.
The fire service said that “the cause is likely to be deliberate however as the incident is ongoing it has yet to be determined”.
It added: “One appliance from Glengormley fire station attended initially, but the fire was inaccessible due to its location on a cliff face and inadequate light.
“Firefighters assessed the situation at first light.
“Firefighters from Carrickfergus fire station extinguished all accessible fire points and prevented the fire spreading further.
“A small area of fire remains inaccessible. Firefighters remain at the scene to monitor the situation. There is no risk to property or life.”