A large wildfire continued burning overnight in the Bannau Brycheiniog National Park after breaking out on Thursday afternoon.
South Wales Fire and Rescue Service said crews remained at the scene on Thursday evening as they tackled the blaze, which affected an area of around 20 square kilometres.
The fire impacted forestry, peat and fine grassland, creating difficult conditions for firefighters working in the area.
Multiple fire appliances, all terrain vehicles and a fire service drone were deployed to the incident, alongside a Wildfire Officer who supported crews in monitoring fire behaviour and directing operations safely.
Firefighters also worked closely with partner agencies including National Trust, Natural Resources Wales and South Wales Police as part of a multi agency response.
Members of the public were urged to avoid affected areas and stay away from outdoor activities around Pen y Fan and surrounding locations while emergency services dealt with the incident.
Residents affected by smoke were also advised to keep doors and windows closed.
The cause of the fire remained unknown on Thursday night. However, the fire service said the blaze came during a period of extremely dry weather and strong winds and followed a number of significant fires attended by crews across South Wales in recent weeks.
South Wales Fire and Rescue Service thanked the public for their patience and cooperation while firefighters continued working in demanding conditions to bring the incident under control.
