Spanish police yesterday arrested 13 suspected neo-Nazi youths for allegedly setting fire to the offices of three political parties, in a bid to disrupt the campaign for the March 12 general elections, officials said. Police said more arrests could follow after the Armageddon National Socialist Brotherhood, a previously unknown group, torched political party offices near the southeastern city of Valencia on Friday. We think that within their terrorist strategy looking to the elections on the 12th, they were going to continue committing attacks of this sort, Valencia Police Chief Segundo Martinez said in remarks broadcast on state radio. Martinez speculated that the group, believed to have links to neo-Nazis in Croatia and Italy, might attempt to strike at a campaign rally or other large gathering. State radio said police ruled out any links between the Valencia fires and two minor bomb blasts yesterday morning, in the northeastern city of Barcelona, that shattered windows of another political party and the government statistics institute.