A powerful car bomb exploded Monday in northern Spain, killing an army officer and wounding six other people in the third attack in 24 hours by suspected members of the Basque separatist group ETA, AP reported. The attack in the northern town of Santona signaled a new ETA offensive just days after the Spanish Supreme Court outlawed two Basque pro-independence parties on grounds they are linked to ETA. The blast, outside an army academy, blew a huge hole in the ground and caused major damage to buildings and cars in the area. The Interior Ministry said the explosion occurred shortly after 1 a.m. (2300 GMT Sunday) as the building was being evacuated because of an ETA bomb warning call. The explosion killed Sergeant-Major Luis Conde de la Cruz, 46. An army captain who was among the six people wounded was in serious condition, a ministry official said. The blast happened as people were being evacuated from the army academy and other buildings following a bomb warning call in the name of ETA to authorities in the neighboring Basque region.