A bomb exploded outside a nightclub in northern Spain after a warning from Basque separatist group ETA but caused no injuries. The bomb, left in a van parked behind the Bordatxo nightclub in the small town of Santesteban, caused extensive damage, Europa Press news agency said. "There has been an explosion in the area of the Bordatxo discotheque, apparently inside a vehicle," a government spokesman in the northern region of Navarre said. He said the club was closed at the time and no one was hurt. The blast followed a telephone warning by ETA to a Basque newspaper and the Basque highway authority, the typical method used by the group to warn of impending bombs.