Seventeen people were injured when a car bomb exploded Thursday in a parking lot at a university in northern Spain, officials said.
One person was also missing after the explosion at about 11 a.m. local time in the city of Pamplona. The force of the blast smashed windows in a building at the University of Navarra.
Spanish National Radio reported that several cars were on fire after the explosion.
"We were lucky with the weather. It's cold and wet and fewer people than usual were walking around the car park," Pamplona's Mayor Yolanda Barcina told La Ser radio. "We are looking for a worker who was supposed to be inside the building. She clocked in and we can't find her."
Basque Country police said a warning call had been received before the explosion but it did not specify where the bomb was.
Amaya Zaratiegui, spokeswoman for the university's clinic, described the blast as "a very strong explosion, very powerful."
Another university building was evacuated after a second call was received following the explosion, Spanish state radio said.
The blast came just two days after Spanish police arrested four suspected ETA guerrillas they said had been planning attacks in the Navarra 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 Navarra.
Authorities blamed the separatists for two bomb attacks that caused no casualties over the weekend in the Basque Country.
Navarra, a region where Pamplona is the capital, is home to many Basque-speakers, and ETA says it should be part of the independent homeland it wants to create.