Firefighters are at the scene of a wildfire in north Sutherland for a fourth day.

About nine square miles (25 sq km) of moorland between Melvich and Strathy has been burned since the fire broke out on Sunday.

Six Scottish Fire and Rescue Service (SFRS) units were at the scene earlier on Thursday, but the number has since been reduced to three.

At one point the blaze affected electricity supplies to 800 homes.

A helicopter has been water bombing the flames and assisting the efforts of firefighters, including retained personnel from Thurso in Caithness, on the ground.

The SFRS has warned of a heightened risk of wildfires across Scotland until Friday due to warm and dry weather.