Police in Spain's Basque region say a bomb has exploded outside a local headquarters of the country's ruling Socialist party.
Police say the bomb went off Monday in the northern town of Lazkao after a warning call from a person claiming to represent the armed Basque separatist group ETA.
Police spotted a backpack next to the headquarters and roped off the area. The backpack exploded soon after causing significant damage to the building but no injuries.
More than 820 people have been killed in ETA's 40 campaign for creation of independent Basque state in northern Spain and southwestern France.
Some information for this report was provided by AFP and Reuters