Two people died this morning when the helicopter they were travelling in crashed in the Valle de Mena near Burgos.
The victims, whose identities have not yet been released, are an employee of a local electrical company, who was checking cables in the area, and the pilot, employed by a private aviation company.
The helicopter appears to have crashed in dense fog into the rocky summit of the surrounding mountains, close to the town of Villasana de Mena, in an area that is only accessible by air.
A search and rescue helicopter is on the scene, being supported by rescue teams from the fire service, the police and the army. Initial rescue operations were hampered by bad weather and poor visibility.