Bilbao - Hundreds of demonstrators in the Basque region's largest city built barricades of burning dumpsters and fought police for control of the streets. Incendiary devices were thrown at the offices of the Basque Nationalist Party. The provocation for the riot was the banning by Spain of pro-independence groups from participating in elections. The Basques are one of Europe's longest-colonized and least-assimilated indigenous cultures, with an equally long history of resistance to the rule of Madrid and Paris.