Two bombs explode in northern Spain's Basque country

(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.