Spanish police say they have arrested a German man suspected of starting a forest fire on the Canary island of La Palma that has claimed the life of a park ranger and forced the evacuation of some 700 people.

The Civil Guard said the 27-year-old was detained Wednesday shortly after the fire started near El Paso town in the west of the island.

Police said it appeared he may have accidentally started the blaze, which continued to rage Thursday.

Acting Prime Minister Mariano Rajoy expressed his condolences for the forest worker on his official Twitter account.

The islands' regional government said some 200 firefighters and army emergency service soldiers were working to extinguish the fire.

It said 700 residents had been evacuated as a precautionary measure.