Madrid  - A car bomb blast killed one person and injured three others at the barracks of the Spanish Civil Guard in the Basque region early Wednesday, according to police.

Part of the building collapsed, burying two policemen at the barracks, 15 kilometres north of Vitoria in Spain's Basque region.

Hours before the strong explosion a telephone warning from an anonymous caller was given to Spanish media.

Though no group has claimed responsibility for the bomb, local media speculated it was the militant Basque separatist group ETA. (dpa)