A telecom centre in the Basque town of Arrigorriaga has been extensively damaged in a bomb blast.
No one was injured in the dynamite blast which happened late last night. Local police suspect the Basque separatist group ETA.
The device was placed at the base of a mobile telephone aerial belonging to the Spanish former state-owned telephone operator Telefonica.
The explosion also damaged nearby private dwellings and parked cars, police said.
Investigators say the material used, a French type of dynamite, was the same as that previously discovered in ETA caches hidden across the border in France.
Just before Christmas, Spanish police arrested seven people and seized a cache of arms including dynamite in a raid on suspected Basque separatists.
Spanish Interior Minister Mr Mariano Rajoy said authorities had also found material to make car bombs when they swooped on apartments and a farm in a village near San Sebastian in the Basque country.
AFP
