Swedish firefighters have called in helicopters to help battle forest fires covering about 1,100 acres in the Halsingsland district north-west of Hudiksvall.

The fires near Hassela and Skån are believed to have been started by a combination of dry weather and sparks from forestry machinery.

Volunteers have joined about 150 firefighters in fighting the blaze, which is expected to take several more days to bring under control.

Swedish news outlet The Local quoted a Holmen official as saying the damage would cost millions of krona and that the company had no insurance covering the value of the forest.