Source (greek only): http://www.imeranews.gr/detail.php?id=38100
According to the newspaper's report unknown persons shot 14 bullets against the Police Station of Agios Vlassios, near Agrinion in Western Greece, Sunday night. Locals say there were two persons on a motorbike.
According to the paper and a report in http://athens.indymedia.org/front.php3?lang=el&article_id=800195 there have preceded one attack with a molotov coctail against a police car and one with erosive materials against an unmarked police car.
Note: finally, turns out they were cops trying to draw attention on the police station in order to go on to a robbery they were planning(!)...