The leader of the armed Basque group ETA was arrested in France on Sunday, officials said, in another setback for the separatists, who have seen five of their commanders taken into custody in the last two years.

The Basque separatist organisation ETA claimed responsibility in a statement issued Sunday for several attacks, including those that killed two Civil Guard officers and a police inspector it called a "torturer".

The explosion came just days after Spain's El Mundo newspaper reported that Spanish authorities had received intelligence reports that three vans had been prepared as car bombs and were expected to cross into Spain from France.

The explosion caused major damage to the barracks and slightly wounded 46 people, mainly from flying glass, and 38 were taken to hospitals, regional ministry representative Miguel Alejo said.

The armed Basque separatist group ETA warned it is planning a new and "effective" campaign of violence after a period of "reflection."