Madrid - Spain's Basque authorities have warned the regional police force that the militant Basque separatist group ETA may be planning an imminent large-scale attack against it, press reports said Thursday.
A part of ETA's Vizcaya complex, regarded as its most important structure, appears to have remained intact despite the arrests of 11 of its suspected members or collaborators, including its leader, last week, the Basque regional Interior Ministry wrote to the police force Ertzainza, instructing it to step up security.
ETA was thought to be planning an attack during some of the summer's regional festivities which draw large amounts of members of the public and police to protect them.