A bomb exploded outside a labour ministry building in Spain's Basque country today after a warning in the name of armed separatist group ETA, causing no injuries.
It was the region's second blast in 24 hours.
Police had no immediate information on the extent of damage to the building, a government centre that provides social services to fishermen in the coastal town of Mutriku, near San Sebastian.
They cordoned off the building after a caller claiming to represent ETA warned Basque newspaper Gara that the bomb was about to explode.
Late yesterday a bomb exploded at a courthouse in nearby Mungia, injuring a police officer.
There was no claim of responsibility in that attack, but it bore the hallmarks of ETA, which regularly targets courts and other public buildings.
On Sunday, a small device exploded at a cash machine in the Basque city of Vitoria, injuring two.
Again, no group claimed responsibility, although two previous bombings this month have been claimed by ETA, which is fighting for an independent Basque homeland.
The series of blasts across the region, six in the last month, is likely to further heighten tension as the Spanish government searches for an end to ETA's 38-year campaign of violence.
On Saturday tens of thousands of protesters marched in Madrid to warn Spain's Socialist government not to negotiate with ETA. Prime Minister Jose Luis Rodriguez Zapatero, who has suggested that an end to ETA's campaign is within sight, has offered talks with the group if they abandon violence but has denied contacts are under way.
ETA, classed as a terrorist group by the European Union and the United States, has killed more than 800 people since 1968.