A car bomb exploded Wednesday outside a regional television station in northern Spain following a warning call from the armed separatist group ETA, police said.

The blast caused significant damage but no injuries.

Police said the bomb exploded shortly after 11 a.m. outside the offices of the EITB station in the center of the northern Basque city of Bilbao. The building had been evacuated and the area cordoned off to traffic following a warning call to a fire department about an hour before the explosion.

"I still don't know how to react. What a way to end the year," EITB presenter Begona Zubieta, who was among several hundred people evacuated, told The Associated Press in a mobile phone message.

Spain's state-run television station broadcast footage showing the explosion. After a flash of fire, the blast blew out dozens of windows on the glass facade of the six-story building. Then a large plume of thick smoke rose up and partially obscured the building.

The attack came less than a month after the fatal shooting of a Basque businessman Dec. 3, for which ETA was blamed.

ETA has killed more than 825 people since 1968 in its campaign for Basque independence. The group declared a cease-fire in March 2006 that led to peace talks. But it broke the truce with a car bomb Dec. 30, 2006 at Madrid's Barajas airport, killing two people.

Police in Bilbao said agents followed tips from the caller Wednesday and found the owner of the vehicle used in the attack tied to a tree in woods just outside Bilbao.

Several politicians visited the scene.

"This is an attack against all Basque society because this is public television paid for by people's taxes," Antonio Basagoiti, head of the regional chapter of the conservative opposition Popular Party, told reporters.

"ETA wants to pressure us in to accepting what they want: independence, socialism, backwardness and a return to the Stone Age," Basagoiti said

With a population of just under 1 million, Bilbao is the Basque region's main city and home to one of the Guggenheim Museums.

It was not immediately clear why, or even whether, ETA had chosen EITB as a target. Several other media outlets are housed in the building, including a bureau of El Mundo newspaper.

ETA's suspected leader was arrested in southern France on Dec. 8. French and Spanish police detained Aitzol Iriondo three weeks after his alleged predecessor, Mikel de Garikoitz Aspiazu, alias Txeroki, was caught.