An office of a moderate nationalist Basque party has been damaged in a bomb attack in the latest sign of anger over the banning of groups accused of supporting ETA.Police say the fire bomb damaged the front of the Basque Nationalist Party building and three cars parked nearby. They say the attack is similar to others carried out in the past by youth groups linked to the armed separatist group. It comes just over a week before elections to the Basque regional parliament, from which radical nationalist parties have been banned. The moderate nationalists, led by Juan Jose Ibarretxe, are on course to win the ballot, according to the latest polls. Spain’s Socialist Prime Minister, Jose Luis Rodriguez Zappatero, has joined campaigning in the Basque region in a late bid to boost his party’s chance.