MADRID, Spain (AP) — A car bomb exploded Friday outside a police station in Spain's northern Rioja region after a warning call from the Basque separatist group ETA, police said.

The bomb went off in the city of Calahorra. There was no immediate word on casualties, but Spanish media said the Civil Guard station area targeted in the attack had been evacuated before the blast.

ETA, which ended a cease-fire in Dec. 2006 after peace talks failed, killed a former town councilor on the Basque region two days before the Spanish general election on March 9.

The group has killed more than 800 people since the late 1960s in its battle to create an independent Basque homeland in northern Spain and southwest France.

A man saying he represented ETA called highway police in the Basque region to warn of the bomb and the explosion came about hour an hour later, the newspaper El Mundo and the Europa press news agency said.