Madrid, Dec 11 (SPA) -- A device exploded outside a post office in the Basque region of northern Spain early on Sunday, causing substantial damage but no injuries, police said. "We don't have any information yet about the kind of device so we can't say whether or not it was (Basque separatists) ETA or street violence or what it was exactly," a police spokesman said. The blast in the town of Igorre near Bilbao damaged the office substantially but did not require the rest of the building, which contained residents, to be evacuated. --SPA 1321 Local Time 1021 GMT www.spa.gov.sa/309689