ATHENS - A far-left militant group claimed responsibility Thursday for a small bomb that exploded in the heart of Athens, saying it had targeted the home of a "vindictive" prosecutor. Greek police said earlier they believed a right-wing bookshop on the ground floor of the prosecutor's apartment building, outside of which the bomb went off on Wednesday night, was the target. The blast, caused by a small explosive device that caused minor damage, came after a phone call was placed to a left-wing newspaper warning of the imminent attack, leading police to cordon off the area.