A car bomb exploded in a car park near the University of Navarre in the northern Spanish city of Pamplona today, slightly injuring several people, officials said.
No telephone warning was received before the bomb exploded at about 11am local time, smashing windows in a university building and damaging nearby cars, officials and witnesses said.
"There were students taking their classes, academic staff in their offices, and they got a fright," university spokesman Jesus Diaz told Spanish radio.
The blast came just two days after Spanish police arrested four suspected ETA guerrillas they said had been planning attacks in the Navarre region.
ETA has killed more than 800 people in four decades of armed struggle for independence of ancient Basque territories in Spain and France, including Navarre.
Authorities blamed the separatists for two bomb attacks which caused no casualties over the weekend in the Basque Country.
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