Tensions are increasing in the Basque region of northwestern Spain, where ETA, a Basque separatist group, has waged a violent campaign for independence for decades. The group declared a cease-fire last September but is furious because police have made sweeps in recent weeks to arrest members of a commando unit and one of its top guerrillas. The group thought it had a tacit understanding that the cease-fire would be met with a similar lack of action on the government’s part. This is not the case, and a return to terrorist attacks could occur.