Fire crews are battling what they are calling a large fire at Tollymore Forest in Co Down.
Emergency teams are evacuating a nearby caravan park because of the blaze at the foot of the Mourne Mountains.
Images online show a fierce fire lighting up the night's sky.
🎥 Current scene of the large fire at Tollymore Forest in Newcastle. Emergency services are dealing with the incident.
— QRadio (@QRadioOfficial) April 21, 2019
Please avoid the Tullybrannigan Road & Bonny’s Caravan Park. pic.twitter.com/cKW1Aiwtpt
The PSNI is asking members of the public to avoid the Tullybrannigan Road and Bonny's Caravan Park in Newcastle.
It says anyone already at the caravan park should leave immediately.
They said in a statement: "Emergency services are currently at the scene of a large fire at Tollymore Forest in Newcastle.
"Police are asking members of the public to avoid the Tullybrannigan Road and Bonny’s Caravan Park.
"Anyone already at the caravan park should leave immediately."