Health warnings have been issued as more than 50 firefighters tackle a large wildfire in Sutherland.
Crews have been battling flames since about 00:04 on Saturday morning at Ben Bhraggie close to the Duke of Sutherland monument near Golspie.
Local residents are being advised to keep windows and doors shut to protect themselves from smoke.
Due to a change of wind direction, smoke is expected to affect air quality within the area around Golspie village.
People with pre-existing respiratory conditions like asthma are being advised to take heed of the advice.
The public are also being asked to stay away from Ben Bhraggie until further notice and to not obstruct helicopter landing sites in the village in any way.
'Complex and challenging'
Group manager Billy McLintock, who was the officer in charge of the incident overnight, said it "remains a complex and challenging incident for crews on the ground".
Fire crews are likely to stay on the scene "for some time", he added.
Elisabeth Smart, a consultant in public health for NHS Highland, said: "The public are being advised to obey all instructions from essential services, to continue to keep away from the area and site and to check SFRS' website for updates.
"The public should keep their windows and doors closed and if there is visible smoke they should remain indoors except for essential travel.
"Anyone exposed to the smoke who develops irritation to the air passages, skin, eyes or respiratory symptoms (coughing, wheezing and breathlessness) or any other unusual symptoms should contact NHS 24.
"Individuals with heart or lung diseases such as asthma should ensure they have access to their dedication especially inhalers and seek medical advice if their symptoms worsen."
Balintore community Fire Station tweeted about the incident, saying: "Crew paged at 14:03 to return to the large wildfire at Golspie.
"The station has been actively involved at this wildfire for 18 out of the last 24 hours. Great commitment from those involved today with fresh crew ready to respond to further calls."
In Aberdeenshire, firefighters returned to the scene of a major gorse blaze at a popular beauty spot.
Crews were initially sent to Bennachie at 19:30 on Saturday to tackle a wildfire covering 200m by 100m.
More than 40 firefighters were needed to bring the blaze under control.
The fire service said some of the gorse reignited on Sunday morning.