Two possible ETA bombs explode in northern Spain

(CNN) -- Two bombs exploded overnight in northern Spain's Basque country, though there were no reports of casualties.

The first occurred without warning shortly after midnight in an industrial pavilion belonging to the Ministry of Labor in the town of Arrigorriaga, reported CNN's partner station, the 24-hour Spanish language news channel CNN Plus.

The second bombing occurred half an hour later in the San Sebastian neighborhood of Donostiarra, but this time authorities had cordoned off the area.

An hour ahead of the attack, a caller had declared to authorities that the attack was imminent and was to be carried out in the name of the separatist group ETA.

Last week, two other bombs were detonated over three days in northern Spain -- both of them preceded by a warning call from ETA.

One of the blasts damaged the recreation center of the ruling Socialist Party in the Basque town of Elgoibar. No one was hurt.

In the other, seven Basque police officers were slightly hurt when a bomb exploded on the outskirts of Bilbao -- also in northern Spain.

ETA threatened the Socialist Party after the re-election in March of Prime Minister Jose Luis Rodriguez Zapatero, and restated its long-standing call for independence for the Basque region.

On March 7, two days before Zapatero won re-election, ETA was blamed for the fatal shooting of a former town councilman from the Socialist Party in a northern Basque town.

The group declared a unilateral cease-fire in March 2006, raising hopes for an end to the violence. However, an ETA bomb at Madrid's airport in December 2006 killed two men, destroyed a parking garage and ended the peace process.

ETA officially terminated the cease-fire in June 2007. Since then the government has blamed it for three killings: two undercover Spanish Civil Guards who were shot dead in France while on an antiterrorist operation against ETA, and the former councilman killed March 7.

ETA is blamed for more than 800 deaths in its long fight for Basque independence. E-mail to a friend

All About Basque Country • ETA Separatist Group