A bomb exploded outside an office of the ruling Socialist Party in the Basque city of Bilbao this morning, wounding three police officers who had cordoned off the area after a warning from ETA.
The bomb, which was hidden in a bag, exploded half an hour after an anonymous caller claiming to represent the Basque separatist group told police where it had been placed.
None of the officers was seriously injured.
The bomb was placed outside an office used by Spain's governing Socialist Party in Bilbao's La Pena neighbourhood.
ETA has killed more than 800 people in four decades of armed struggle. Its last fatal attack was on March 7th when, two days before a general election, it shot dead a former Socialist Party councillor in the Basque town of Mondragon.