Spanish police on Sunday prevented a major attack in Seville by defusing a car bomb packed with 100 kg (220 pounds) of explosives believed to have been planted by the Basque separatist group ETA, officials said. The bomb was left in a car stolen from France and parked in front of a Social Security office next door to a hotel and near a train station in Seville, one of Spain's most important cities, located in the southern region of Andalusia. About 100 guests at the hotel were evacuated until the bomb was defused and high-speed rail traffic to and from the Santa Justa station was halted for half an hour as a precaution. Callers identifying themselves as members of ETA alerted authorities to the bomb in the early morning hours. The warning gave police time to defuse the device. Their objective could have been to destroy the nearby buildings or to attack the Tedax (bomb squad), but for now these are just hypotheses, Jose Torres Hurtado, the central government delegate in Seville, told Reuters. We have avoided a major attack, he told state radio. ETA is blamed for 23 killings this year and around 800 since 1968 in its campaign for an independent Basque homeland in northern Spain and southwestern France. It typically targets low-level politicians or security forces and sometimes tips off police to big bombs to lure them into a trap or to sow fear among the public by demonstrating an ability to attack at will.